I was 9 years old when Nelson Mandela was sent to prison on Robben Island. As a boy, I learned about him in school, and I remember seeing reports about the anti-Apartheid movement on the evening news. Decades later, I got to meet him and work with him. In person he was even more inspiring than I had imagined. His humility and courage left an impression that I will never forget.

So it was a special honor to be invited to give the Nelson Mandela Lecture in Pretoria, South Africa. I eagerly accepted the invitation and quickly began working on my remarks.

I decided to share my optimism about Africa’s future—to explain why I think the continent has the potential to change faster in the next generation than any continent ever has.

It’s because Africa is the world’s youngest continent, and youth can go hand in hand with a special dynamism. I was 20 years old when Paul Allen and I started Microsoft. The entrepreneurs driving startup booms in Johannesburg, Lagos, and Nairobi are just as young, and the thousands of businesses they’re creating are already changing lives across the continent. The potential will only grow as the digital revolution brings more advances in artificial intelligence and robotics.

But positive change across Africa won’t happen automatically. The real returns will come only if Africans can unleash this talent for innovation in all of the continent’s growing population. That depends on whether all of its young people are given the opportunity to thrive.

It is still an open question, and it is the crux of my speech, which I gave today at the University of Pretoria. It was an honor to give this lecture, and I’m grateful to the Nelson Mandela Foundation and the university for inviting me. You can read my full speech below the video.

BILL GATES:

Well, thank you. Good evening, ladies and gentlemen. Graça Machel, Professor Ndebele, Vice Chancellor de la Rey, members of the Mamelodi families, friends and dignitaries.

I can’t think of a greater honor than giving a lecture named after Nelson Mandela.

I’m also thrilled that the theme of this lecture this year is “living together.”

It’s truly fitting because in many ways, “living together” was also the theme of Nelson Mandela’s life.

The system he fought against was based on the opposite idea—that people should be kept apart, that our superficial differences are more important than our common humanity.

Today, South Africans are still striving to “live together” in the fullest sense. But you are so much closer to that ideal because Nelson Mandela and so many others believed in the promise of one South Africa.

I was only nine years old when Nelson Mandela was sent to Robben Island. As a boy, I learned about him in school. I remembered seeing reports about the anti-Apartheid movements regularly on the evening news.

The first time I got to speak to him was in 1994 when he called me to help fund South Africa’s election.

I was running Microsoft, and largely focused on software most of the time, but I admired him so much, and I knew the election was historic. So I did what I could to help.

My first trip to Africa had been just the year before that in 1993 when my wife Melinda and I had traveled to East Africa.

The landscape was beautiful, the people were friendly, but the poverty there, which we were seeing for the first time, disturbed us. It also energized us.

Obviously, we knew parts of Africa were poor, but being on the continent turned what had been an abstraction into an injustice we couldn’t ignore.

Melinda and I had always known that we’d give our wealth to philanthropy eventually. But when we were confronted with such glaring inequity, we started thinking about how to take action sooner.

This sense of urgency was further spurred on by another trip in 1997 when I came to Johannesburg for the first time as a representative of Microsoft.

I spent most of the time in the richer part of the city in business meetings, but I also went to the community center in Soweto where Microsoft was donating computers.

My visit to Soweto, which was quite different then than it is now, taught me how much I had to learn about the world outside the comfortable bubble I’d lived in all my life.

As I walked into the community center, I noticed there weren’t any electrical connections. To keep the computer on, the one I was donating, they had rigged up an extension cord connected to a diesel generator outside. I realized the minute I left, the generator would get moved to something more important.

So as I read my remarks about the importance of the technology gap, I knew that it was only a small part of the story. Computers could help people do very important things, and in fact, they are part of how life on the continent can be revolutionized. But computers alone can’t feed disease or cure children. And if they can’t be turned on, they can’t do much at all.

So after that, Melinda and I moved to start our foundation because the cost of waiting had become clear.

Our work is based on the simple idea that every person, no matter where they live, should have the opportunity to lead a healthy and productive life.

We’ve spent the past 15 years learning about the issues and looking for the leverage points where we can do the most to help people seize their opportunity.

It was when I started coming to Africa regularly for the foundation that I got to know Nelson Mandela personally. AIDS was one of the first issues our foundation worked on, and Nelson Mandela was both an advisor and an inspiration.

One thing we talked about was the stigma around AIDS. So I remember 2005 very clearly when his own son died of AIDS. Rather than stay silent about the cause of his son’s death, Nelson Mandela announced it publicly because he knew that stopping the disease required breaking down the walls of fear and shame that surrounded it.

It is important to recall Nelson Mandela’s legacy, and I’m grateful for the opportunity to do so.

But Nelson Mandela was concerned about the future. He believed people could make the future better than the past. And so that’s what I want to focus on for the remainder of my talk.

What can South Africa become? What can Africa become? What can the world become? And what must we do to make it that way?

The Millennium Development Goals adopted by the United Nations in 2000 laid a foundation that enabled the world, including Africa, to achieve extraordinary progress over the last 15 years.

And the Sustainable Development Goals that recently replaced them set even more ambitious targets for creating the better world we all want.

When I talk about progress, I always start with child survival because whether children are living or dying is such a basic indicator of a society’s values.

Since 1990, child mortality in sub-Saharan Africa has been reduced by 54 percent. That means one million fewer children dying each year compared to 25 years ago.

Ten African countries achieved the very ambitious MDG target of reducing child mortality by over two-thirds.

At the same time, the incidence of poverty and malnutrition is down. And though economic growth has slowed in the past few years, it’s been very robust in many African countries for more than a decade.

This is real progress, but the Africa Rising narrative doesn’t tell the whole story about the life on the continent.

First, the progress have been uneven. You know this very well here in South Africa.

In last year’s Nelson Mandela Annual Lecture, the French economist, Thomas Piketty, pointed out that income inequality in South Africa is, quote, “higher than pretty much anywhere else in the world.”

In general, African countries tend to have higher rates of inequality than countries on other continents.And despite healthy average GDP growth in the region, many countries have not yet shared in it.  Inequalities exist within countries and between countries.

So until progress belongs to all people everywhere, the real promise of living together will remain elusive.

Second, even with the great progress Africa has made, it still lags behind the rest of the world in most indicators. In sub-Saharan Africa, one in 12 children still die before they turn five. Now, that’s a vast improvement compared to 25 years ago, but African children are still 12 times more likely to die than the average child in the world.

And because rates of poverty and malnutrition aren’t shrinking as fast as the population is growing, the number of people who are poor or malnourished has actually gone up since 1990.

Finally, the progress is fragile. The continent’s two largest economies, here in South Africa and in Nigeria, are facing serious economic challenges. And new threats require attention. The Ebola crisis pointed out weaknesses in many national health systems. The effects of climate change are already being felt among farmers in many countries.

In short, to meet the ambitious goals of the Sustainable Development Goals, Africa needs to do more, do it faster, and make sure everybody benefits. It won’t be easy, but I believe it can be done.

The successes and failures of the past 15 years have generated examples and lessons we can follow. Phenomenal advances in science and technology are expanding the range of solutions available to solve development challenges. And then there is the ingenuity of the African people.

One topic that Nelson Mandela came back to over and over again was the power of youth. He knew what he was talking about because he started his career as a member of the African National Congress Youth League when he was still in his 20s.

Later on, he understood that highlighting the oppression of young people was a powerful way to explain why things must change. There is a universal appeal to the conviction that youth deserve a chance.

I agree with Mandela about young people, and that is one reason I am optimistic about the future of this continent. Demographically, Africa is the world’s youngest continent. And its youth can be the source of a special dynamism.

In the next 35 years, two billion babies will be born in Africa. By 2050, 40 percent of the entire world’s children will live on this continent.

Economists talk about a demographic dividend. When you have more people of working age and fewer dependents for them to take care of, you can generate phenomenal economic growth. Rapid economic growth in East Asia in the 1970s and 1980s was partly driven by the large number of young people moving into their workforce.

But, for me, the most important thing about young people is the way their minds work. Young people are better than old people at driving innovation because they’re not locked in by the limits of the past.

When I started Microsoft at the age of 19, computer science was a young field. We didn’t feel beholden to old notions about what computers could or should do. We dreamed about the next big thing and we scoured the world around us for the ideas and tools that would help us create it.

But it wasn’t just Microsoft. Steve Jobs was 21 when he started Apple. Mark Zuckerberg was only 19 when he started Facebook.

The African entrepreneurs driving startup booms in the Silicon Savannahs from Johannesburg and Cape Town to Lagos and Nairobi are just as young in chronological age, but also in their outlook. The thousands of businesses they’re creating are already changing daily life across the continent.

In a few days, I’ll be meeting with some of these young innovators. People like the 21-year-old who founded Kenya’s first software coding school to provide other young people with computer programming skills. And like the 23-year-old social entrepreneur here in South Africa who manufactures school bags from recycled plastic shopping bags. Besides being highly visible to protect children as they’re walking to school, these school bags sport a small solar panel that charges a lantern during the journey to and from school, providing illumination so students can study at home.

The full returns will come if we can multiply this talent for innovation by the whole of Africa’s growing youth population. That depends on whether Africa’s young people—all of Africa’s young people—are given the opportunity to thrive.

Nelson Mandela said, “Poverty is not natural, it is man made and it can be overcome and eradicated by the actions of human beings.”

We are the human beings that must take action. And we have to decide now because this unique moment won’t last. We must clear away the obstacles that are standing in young people’s way so that they can seize all of their potential.

If young people are sick and malnourished, their bodies and brains will never fully develop. If they are not educated well, their minds will lie dormant. If they do not have access to economic opportunities, they will not be able to achieve their goals.

But if we invest in the right things, if we make sure the basic needs of Africa’s young people are taken care of, then they will have the physical, cognitive, and emotional resources they need to change the future. Life on this continent will improve faster than it ever has. And the inequities that have kept people apart will be erased by broad-based progress that is the very meaning of the words “living together.”

When Melinda and I started our foundation 15 years ago, we asked ourselves: What are the areas of greatest impact? It was clear to us that investing in health was high on the list. When people aren’t healthy, they can’t turn their attention to other priorities. But when health improves, life improves by every measure.

Over the last 15 years, our foundation has invested more than $9 billion in Africa. And we are committed to keep on investing to help Africa.

In the next five years, we will invest another $5 billion.

Some of this money has gone into discovering and developing new and better vaccines and drugs to help prevent infectious disease. We’ve also invested in global partnerships that work closely with countries across the continent to get these solutions to the people who need them most.

We’ve been fortunate to work with amazing partners, and together we’ve seen incredible progress.

For example, the entire continent of Africa has been polio free for two years, which puts us within reach of wiping polio out from the face of the earth forever.

The newest vaccines that protect children from two of the most devastating diseases—pneumonia and diarrhea—are reaching children across Africa at the same time they’re available for children in wealthier countries.

Countries that invest in strong, community-based primary healthcare systems—including Malawi, Ethiopia, and Rwanda—are making great progress reducing child mortality.

Malaria infections and deaths are down significantly thanks to better treatment and prevention tools.

And efforts like the Ouagadougou Partnership in West Africa are helping millions of women get access to contraceptives, which make it easier for them to care for their families.

HIV/AIDS is another area where there’s been good progress. Though it’s a complicated story, and there are still big challenges ahead.

In a few days, I’ll be speaking at the International AIDS Conference in Durban. When the global AIDS community last met there in 2000, only a few thousand Africans were receiving antiretroviral drugs. Today, more than 12 million Africans are on treatment, more than a quarter of them living here in South Africa.

So this is a huge achievement, and millions of lives have been saved. But the rate of new infections remains high. In sub-Saharan Africa, more than 2,000 young people under the age of 24 are infected every single day. The number of young people dying from HIV has increased fourfold since 1990.

We need to get people to get diagnosed, we need people to seek treatment, and people who are on treatment need to be fully adherent.

Along with HIV, we have high rates of tuberculosis, including here in South Africa where TB/HIV co-infection continues to wage a devastating toll.

So we need more creative ways to make testing and treatment accessible and easier to use.

We need to get much more out of existing prevention methods like condoms, voluntary medical male circumcision, and oral anti-HIV medicine.

And we’re going to have to invent new and better preventative solutions like medicines you only have to take once a month or an effective vaccine.

If we don’t act both on today’s treatment and create these tools, the hard-earned gains made against HIV in sub-Saharan Africa over the last 15 years could actually be reversed. Because of the population growth, just doing what we are today is not enough. We need to do more.

Nutrition is another critical area of focus for Africa. Nearly one-third of the continent’s children suffer from malnutrition that stunts their growth and robs them of their physical and cognitive potential. Millions more suffer from micronutrient deficiencies. These are impacts that last a lifetime and impact whole generations of African youth.

African Development Bank President Akin Adesina put it best when he said recently that the greatest contributor to Africa’s economic growth is not physical infrastructure, but gray matter infrastructure, people’s brainpower. The best way to build that infrastructure includes proper nutrition.

Without eliminating malnutrition, we won’t get the great potential that’s there.

We know that when mothers and infants get good nutrition, that breast feeding is a key part of that. We know that certain vitamins and minerals are essential for children.

We have a number of ways to intervene to help nutrition, things like fortified cooking oil, sugar fortified with vitamin A, and sugar and flour enriched with iron, zinc, and vitamin B.

One of the most exciting advances is the breeding of crops so they are naturally more nutritious. For example, when adolescents eat high-iron pearl millet, their likelihood of iron deficiency is reduced six-fold.  And just half a cup of biofortified orange sweet potato is all it takes to meet a child’s daily vitamin A needs.

The toll of micronutrient deficiency is huge, but the costs of fighting it are not.

Recent estimates done in Nigeria and Uganda indicate that every dollar invested to reduce stunting returns $17 in greater earning capacity in the workplace.

When children’s bodies and brains are healthy, the next step is an education that helps them develop the knowledge and skills to become productive contributors to society.

Improving education is hard work. I’ve learned this first hand through our foundation’s efforts to create better learning outcomes for primary, secondary, and university students in the United States.

But this hard work is incredibly important. A good education is the best lever we have for giving every young person a chance to make the most of their lives.

In Africa, as in the United States, we need new thinking and new educational tools to make sure that a high-quality education is available to every child.

In Uganda, young innovators at the NGO called Educate! are helping high schools prepare young people for the workplace by teaching students how to start their own business.

And with the high level of mobile phone penetration in Africa, technology using mobile phones to connect to the Internet have the potential to help students build foundational skills while giving teachers better feedback and support.

Globally, the educational technology sector is innovating and growing rapidly and it’s exciting to see new models and tools emerging to meet the needs of educators and students who are not connected to current systems.

At the university level, we need not only to broaden access, we have to also ensure that we have high-quality public universities that will launch the next generation of scientists, entrepreneurs, educators, and government leaders.

South Africa is blessed with some of the best universities in Africa, like the one we’re at today.

For our foundation, we partner with these universities to do our work in health and agricultural research. Maintaining the quality of this country’s higher-education system, while expanding access to more students will not be easy, but it is critical to South Africa’s future.

Other countries in the region will do well to follow South Africa’s example and provide the highest-level university education to the largest number of qualified students.

Healthy, educated young people are eager to make their way in the world. But Africa’s youth must have economic opportunity to channel their energy into progress.

Some of those youths will work in agriculture, where still over half of the workforce toils today.

We need advances to make agriculture far more productive. Today, the seeds that are used are unproductive, the soils are not very good, and so many farmers grow just enough to feed their family.

With climate change leading to more severe weather, doing more of the same will not be good enough.

The key to this is a series of innovation at every step along the way from farm to market.

First, farmers need better tools to avoid disasters and grow surplus. Things like seeds that can tolerate drought, floods, pests, and disease; affordable fertilizers that have the right mix of nutrients to replenish the soil; and easy-to-administer livestock vaccines that can help prevent flocks and herds from being wiped out.

Next, farmers need to be connected to a market where they can buy these inputs at a good price, and sell their surplus, and earn a profit that they can invest not only in their family’s basic needs, but also back into the farm.

This, in turn, will provide employment opportunities both on and off the farm as more prosperous farmers begin to support a range of agribusinesses like seed dealers, trucking companies, and processing plants.

I recently met with a group of young crop breeders, one from Ethiopia, one from Kenya, one from Nigeria, one from Uganda. I really love talking about the science of plant productivity. And in this case, I was amazed at the expertise all of these scientists brought to their work on cassava, a staple crop that provides more than one-third of the calories in many African diets.

Some had ways of improving the nutritional content of cassava. Others were breeding a variety that can resist both of the devastating diseases that are threatening to wipe out the cassava crop.

Our foundation is also working with a young computer scientist from Makerere University who designed a mobile phone app that lets farmers upload a picture of their cassava plants to find out whether it’s infected or not.

These are examples of the kind of innovators who can drive an agricultural transformation across the continent if they have the support they need. For many decades, agriculture has suffered from dramatic underinvestment. Many governments didn’t see the link between their farmers and economic growth.

Now, however, this misconception is gone. And through the Comprehensive African Agricultural Development Program, countries have a framework for transforming agriculture. The investment needs to follow so that young Africans have the means to create the thriving agriculture they envision.

With Africa’s farms as a base, the next step in economic growth is to promote job creation in other sectors. Doing this will require investment in infrastructure including energy.

Seven in 10 Africans lack access to power, which makes it harder to do everything. Harder to get healthcare in a dark clinic. Harder to learn in school when it’s boiling hot. Harder to be productive when you can’t use labor-saving machinery.

Ultimately, a shortage of power, like many African countries—including South Africa—have experienced, is also a drag on economic growth.

Businesses will not invest fully in places where they can’t operate efficiently.

A recent report projected that 500 million Africans won’t have electricity even in 2040. We need to change that.

What Africa needs is what the whole world needs: An energy advance that provides cheap, clean energy for everyone.

I’ve spent a lot of my time in the last two years working on this issue because it’s such an important advance.  I’m involved with a group of business people who are collaborating with governments to not only increase energy R&D, but also to vastly increase the private investment in this area.

I get angry when I see that Africa is suffering the worst effects of climate change, although Africans had almost nothing to do with causing this.

The rich countries need to follow through on their commitment to double their energy R&D budgets so that we get the breakthroughs that are applicable globally, and we need to do that urgently.

Africa needs power now. And so there are many pragmatic steps we need to take even in advance of these new inventions.

In parts of Africa, there’s hydro and geothermal sources which are both reliable and renewable that can be exploited. There’s been a lot of work on small-scale grids and the use if micro solar. This approach can provide individuals with electricity for basic purposes, but we also need large-scale power including well-managed electrical grids.

It means organizing the power system so that it’s economic, so that the electronic bills are paid for, and so that the network is reliable 100 percent of the time.

Once we get economic viability for these utilities, then it bootstraps the economy. It allows investments that are job creating.

So there are many challenges that I’ve laid out here: Challenges in health, education, agricultural productivity, energy, and creating enough job opportunities.

These advances only happen in the context of governments that function well enough to enable them. I applaud initiatives like Mo Ibrahim’s Annual Index of African Governments, which looks objectively at multiple measures of government performance in each country on the continent.

Citizens in other regions would be well served by this kind of comprehensive effort to spotlight and spread effective governance.

A lot can be accomplished by focusing on fiscal governance and accountability. Here in South Africa, the government gets strong marks for the budget information it provides to the public.

The International Budget Partnership, an independent monitoring organization, also ranks South Africa highly for its oversight of government spending.

In some countries, individual citizens are leading the way. In Nigeria, 30-year-old Oluseun Onigbinde gave up a career in banking years ago to devote himself full time to pulling back the curtain on the Nigerian federal expenditure.

With savvy use of data and social media, he founded BudgetIT Nigeria, which provides facts and figures the average Nigerian can understand. No doubt, he’s a thorn in the side of some of Nigeria’s elite, but to me he’s an example of what one person can do to make a difference.

Governments have an opportunity not only to learn from what’s been done in the past, but to do things in new ways. One of the exciting prospects is the role they can play in accelerating use of digital technology to leapfrog traditional models and costly infrastructure associated with banking and delivery of government services.

By using mobile phones, tens of millions of people are already storing money digitally and using their phones to make purchases as if they were debit cards.

A good example of this is M-PESA in Kenya. These services don’t just give people a better way to move money around, they give people a place to save cash to fund a startup of a micro enterprise or pay a child’s school fee. They create informal insurance networks of friends and families who can help with unexpected shocks. And they increase the profitability of small businesses by lowering transaction costs, making it easy to order products and supplies, and having greater security of financial assets.

A digital financial connection can also help governments deliver services more efficiently. Studies from India show the government able to save tens of billions a year by connecting households to a digital payment system and automating all government payments.

The early evidence suggests that similar programs in Africa can also yield substantial benefits. For example, recent research in Uganda showed that providing people with digital cash transfers rather than direct food subsidies not only saved the cost of delivery, it also improved nutrition because recipients used the money to purchase a greater diversity of foods and to space out meals as needed.

Governments can accelerate this digital transformation by implementing policies that encourage commercial investment, innovation, and healthy competition.

Countries like Kenya, Tanzania, and Nigeria are already investing in the building blocks of this new digital financial platform. And I believe they’ll see substantial positive returns.

If there’s one thing I’m sure of, it’s this: Africa can achieve the future it aspires to.

That future depends on the people of Africa working together across economic and social strata and across national borders to lay a foundation so that Africa’s young people have the opportunities they deserve.

Recently, I had a meeting with students at Addis Ababa University. I started asking them the kinds of questions you would ask college students in the United States like, “What do you want to do after you graduate? What fields are you thinking of going into?”

They looked at me like I was kind of crazy for asking those questions. Each of them had a plan for their future. They felt their parents had sacrificed for decades so they could go to this university. They weren’t weighing their options, they had come to the university to get specific training, and they were eager to take that training and use it to make their country more prosperous.

They saw themselves as part of a large community with great needs.And they were going to dedicate themselves to serving that community by meeting those needs.

I see that sense of purpose when I come to Africa, and especially when I talk to young Africans. I think it’s a unique asset that people see the need to change and that they want to give back.

The students here believe not only in themselves, they also believe in their countries and the future of the continent. Our priority is to make sure they have the opportunity to turn those beliefs into action because young people with this sense of purpose can make the difference between stagnation and faster progress.

Nelson Mandela said, “Young people are capable, when aroused, of bringing down the towers of oppression and raising the banners of freedom.” But our duty is not merely to arouse, our duty is to invest in these young people, to put in place the basic building blocks so they can build the future.

And our duty is to do it now because the innovations of tomorrow depend on the opportunities available to children today.

I’m sure it’s clear to everyone that these are big and complicated challenges. But it’s just as clear that people with bravery, energy, intellect, passion, and stamina can face big, complicated challenges and overcome them.

There is so much more work to be done to create a future in which we can all live together, but there are also so many people who are eager to get to work.

Let’s do everything within our power right now to help build the future that Nelson Mandela dreamed of and the future that we will achieve together.

Thank you.