Aaron Huey's effort to photograph poverty in America led him to the Pine Ridge Indian Reservation, where the struggle of the native Lakota people -- appalling, and largely ignored -- compelled him to refocus. Five years of work later, his haunting photos intertwine with a shocking history lesson.

Activist and fundraiser Dan Pallotta calls out the double standard that drives our broken relationship to charities. Too many nonprofits, he says, are rewarded for how little they spend -- not for what they get done. Instead of equating frugality with morality, he asks us to start rewarding charities for their big goals and big accomplishments (...

Sure, sports are about athleticism -- but what actually keeps fans invested? Journalist Kate Fagan takes a fascinating deep-dive into lesser-known moments in women's sports history and its media coverage, revealing why stakes and storylines are at the heart of what makes sports riveting.

Design legend Michael Bierut tells the story of the accidental success of one of the most famous maps in the world -- the London Tube Map.

2013 was a year of hype for MOOCs (massive open online courses). Great big numbers and great big hopes were followed by some disappointing first results. But the head of edX, Anant Agarwal, makes the case that MOOCs still matter -- as a way to share high-level learning widely and supplement (but perhaps not replace) traditional classrooms. Agarw...

Stairs don't just get you from point A to point B. Architect David Rockwell explains how they shape your movement -- and your feelings.

While news from Iran streams to the world, Clay Shirky shows how Facebook, Twitter and TXTs help citizens in repressive regimes to report on real news, bypassing censors (however briefly). The end of top-down control of news is changing the nature of politics.

Astronomers once gazed upon the night sky and counted every star in the galaxy by hand. The process has evolved since then, but the thirst for celestial knowledge remains the same. Join astrophysicist Emily Levesque for an anecdote-rich jaunt through the technological history of photographing the cosmos and learn about the one constant that make...

Your teeth carry secrets: centuries of history about your ancestors, from where they lived to what they ate and where they traveled. Bioarchaeologist Carolyn Freiwald traces the story of human migration across the Americas -- from Mayan royalty and Belizean buccaneers to rural Appalachian farmers -- to illustrate what ancient teeth can reveal ab...

A clay cylinder covered in Akkadian cuneiform script, damaged and broken, the Cyrus Cylinder is a powerful symbol of religious tolerance and multi-culturalism. In this enthralling talk Neil MacGregor, Director of the British Museum, traces 2600 years of Middle Eastern history through this single object.

Coming to us from 50 years in the future, legendary sci-fi writer Kim Stanley Robinson tells the "history" of how humanity ended the climate crisis and restored the damage done to Earth's biosphere. A rousing vision of how we might unite to overcome the greatest challenge of our time.

Throughout the history of Islam, says journalist Bobby Ghosh, there have been two sides to jihad: one, internal, a personal struggle to be better, the other external. A small minority has appropriated the second meaning, using it as an excuse for deadly global violence against "the West." Ghosh suggests it's time to reclaim the word.

How can we begin to address the global, insidious problem of climate change — a problem that's too big for any one country to solve? Economist Nicholas Stern lays out a plan, presented to the UN's Climate Summit in 2014, showing how the world's countries can work together on climate. It's a big vision for cooperation, with a payoff that goes far...

To achieve lasting change sometimes requires the hard, even radical, choice of partnering with people you'd least expect. Justice reform advocate Nisha Anand shares her story of working with her ideological opposite to make history and save lives -- and urges us all to widen our circles in order to make progress with purpose.

"Ideas can and do change the world," says historian Rutger Bregman, sharing his case for a provocative one: guaranteed basic income. Learn more about the idea's 500-year history and a forgotten modern experiment where it actually worked -- and imagine how much energy and talent we would unleash if we got rid of poverty once and for all.

Daniel Libeskind builds on very big ideas. Here, he shares 17 words that underlie his vision for architecture -- raw, risky, emotional, radical -- and that offer inspiration for any bold creative pursuit.

15th century Europeans believed they had hit upon a miracle cure: a remedy for epilepsy, hemorrhage, bruising, nausea and virtually any other medical ailment. It was a brown powder known as "mumia," and was made by grinding up mummified human flesh. But just how common is human cannibalism, and how do cultures partake in it? Bill Schutt explores...

Marc Pachter has conducted live interviews with some of the most intriguing characters in recent American history as part of a remarkable series created for the Smithsonian's National Portrait Gallery. He reveals the secret to a great interview and shares extraordinary stories of talking with Steve Martin, Clare Booth Luce and more.

In his long career as a religious evangelist, the Rev. Billy Graham spoken to millions around the world and served as advisor to US presidents.

Trinidad and Tobago amassed great wealth in the 1970s thanks to oil -- but 2 out of every 3 dollars earmarked for development ended up wasted or stolen. This fact has haunted Afra Raymond for 30 years. Shining a flashlight on a continued history of government corruption, Raymond gives us a reframing of financial crime.

It's called the "Flynn effect" -- the fact that each generation scores higher on an IQ test than the generation before it. Are we actually getting smarter, or just thinking differently? In this fast-paced spin through the cognitive history of the 20th century, moral philosopher James Flynn suggests that changes in the way we think have had surpr...

Can we rebuild our broken suburbs? Ellen Dunham-Jones shares a vision of dying malls rehabilitated, dead "big box" stores re-inhabited, and endless parking lots transformed into thriving wetlands.

With astronaut eyes and ethnographer curiosity, Tricia Wang helps corporations grow by discovering the unknown about their customers.

Immersing himself in alternate lifestyles and hilarious experiments (usually with himself as the guinea pig), writer A.J. Jacobs tests the limits of behavior, customs, culture -- and reports back on the wisdom and practical knowledge he's gained.

Hundreds of meters below the surface of the ocean, Laura Robinson probes the steep slopes of massive undersea mountains. She's on the hunt for thousand-year-old corals that she can test in a nuclear reactor to discover how the ocean changes over time. By studying the history of the earth, Robinson hopes to find clues of what might happen in the ...

At TEDGlobal 2010, author Matt Ridley shows how, throughout history, the engine of human progress has been the meeting and mating of ideas to make new ideas. It's not important how clever individuals are, he says; what really matters is how smart the collective brain is.

Child prodigy Adora Svitak says the world needs "childish" thinking: bold ideas, wild creativity and especially optimism. Kids' big dreams deserve high expectations, she says, starting with grownups' willingness to learn from children as much as to teach.

In keeping with the theme of TED2008, professor Stephen Hawking asks some Big Questions about our universe -- How did the universe begin? How did life begin? Are we alone? -- and discusses how we might go about answering them.

Economist Yasheng Huang compares China to India, and asks how China's authoritarian rule contributed to its astonishing economic growth -- leading to a big question: Is democracy actually holding India back? Huang's answer may surprise you.

What can you hear in silence? In this exploration of sound, host of the podcast "Twenty Thousand Hertz" Dallas Taylor tells the story of arguably the most debated musical composition in recent history -- composer John Cage's iconic piece 4'33" -- and invites you to take notice of the soundscape around you. Watch to the end to experience a perfor...