In 19th century Europe, with nation building well under way, thoughts turned outward, toward empire. This week, we're looking at how Europeans expanded into Africa, Asia, and Oceania during the 1800s. You'll learn about China and the...

Many African countries are poor for a simple reason, says entrepreneur Magatte Wade: governments have created far too many obstacles to starting and running a business. In this passionate talk, Wade breaks down the challenges of doing...

In the African grasslands, a gazelle suffering from tuberculosis takes its last breath. The animal's corpse threatens to infect the water, but for the vulture, this isn't a problem: it's a feast. With a stomach of steel that can digest...

Many people across the world don't have access to healthy food -- while in other places tons of food go to waste. Social entrepreneur Ndidi Okonkwo Nwuneli thinks we can take bold steps to fix this problem. She lays out what it would...

In this video Paul Andersen explains how immune individuals in a population give the entire group a herd immunity. Concepts of immunity, vaccines, basic reproduction number, and herd immunity threshold are discussed.

There are all sorts of flying birds, but some of the world's biggest are ones that stick to the ground, like the awesome ostrich!

International aid groups make the same mistakes over and over again. David Damberger analyzes his own engineering failure in India -- and calls for his friends in the development sector to publicly admit, scrutinize and learn from their...

Louise Leakey asks, "Who are we?" The question takes her to the Rift Valley in Eastern Africa, where she digs for the evolutionary origins of humankind -- and suggests a stunning new vision of our competing ancestors.

In sub-Saharan Africa, HIV infections are more prevalent and doctors scarcer than anywhere else in the world. With a lack of medical professionals, Mitchell Besser enlisted the help of his patients to create mothers2mothers -- an...

As the world's population grows and the effects of climate change come into sharper relief, we'll have to feed more people using less arable land. Molecular biologist Jill Farrant studies a rare phenomenon that may help: "resurrection...

* Viewer discretion advised. This video includes discussion of mature topics and may be inappropriate for some audiences. We teach girls that they can have ambition, but not too much ... to be successful, but not too successful, or...

In which John Green teaches you about nonviolence and peace movements in the 20th century. What is nonviolence? What is a peace movement? Well. traditionally, humans often resort to violence when they come into conflict. In the 20th...

So you know about Freshwater and Saltwater now and you know that there's not that much Freshwater for us (and other life) to get to. So how do different animals deal with different amounts of water where they live? In this episode of...

For thousands of years, people made both functional maps and what are known as cosmographies, illustrating the earth and its position in the cosmos, often including constellations, gods, and mythic locations. These maps were meant to...

At 18, Natalie Warne's work with the Invisible Children movement made her a hero for young activists. She uses her inspiring story to remind us that no one is too young to change the world.

Around 750-1250 CE, the Islamic empire made incredible scientific advancements that still influence many fields of research today. What we know about some of the great minds of that time, as well as what we’ve learned from modern...

Born out of a social media post, the Black Lives Matter movement has sparked discussion about race and inequality across the world. In this spirited conversation with Mia Birdsong, the movement's three founders share what they've learned...

Chika ezeanya-esiobu wants to see Africans unleash their suppressed creative and innovative energies by acknowledging the significance of their indigenous, authentic knowledge. In this powerful talk, she shares examples of untapped,...

Hank scares our pants off with a tale of the five deadliest infectious diseases in the world.

In this short, image-packed talk, Marisa Fick-Jordan talks about how a village of traditional Zulu wire weavers built a worldwide market for their dazzling work.

Vaccines save millions of lives each year, so we owe a lot to the people that pioneered that medical breakthrough. But the concept of a vaccine had already existed for a long time before it was “discovered,” and the real story is way...

Talking at the US State Department this summer, Hans Rosling uses his fascinating data-bubble software to burst myths about the developing world. Look for new analysis on China and the post-bailout world, mixed with classic data shows.

It is time to close the funding gap for Black female-led start-ups the world over, says entrepreneur Temie Giwa-Tubosun, whose company LifeBank delivers life-saving medical supplies to remote areas in Africa. Today, LifeBank operates...

Jane Goodall is an amazing scientist and conservationist who has dedicated her life to learning about and protecting chimpanzees! Thanks to her, we've learned that, sometimes, people and animals aren't so different! Learn more about her...