Moments of crisis can upend our lives, but can also help define them. This episode, TED speakers explore how a quick, compassionate or unexpected response can turn crisis into opportunity. Guests include physician Ken Kamler, motivational speaker Matt Weinstein, Melissa Fleming of the United Nations High Commissioner for Refugees, activist Nancy Lublin and photojournalist Kitra Cahana. (Original broadcast date: April 1, 2016)

What lies beyond the reach of the naked eye, and how do these hidden forces shape our lives? This hour, TED speakers reveal forgotten cities, underwater canyons, tiny parasites, and a boiling river. TED speakers include computer scientist Abe Davis, ocean explorer Robert Ballard, science writer Ed Yong, space archaeologist Sarah Parcak, and geoscientist Andrés Ruzo. (Original broadcast date: March 18, 2016)

This hour, we'll hear from TED speakers who share an infectious sense of wonder and curiosity about our place in the universe and what lies beyond our skies. TED speakers include physicist Brian Greene, astronomer Phil Plait, and astronomer Jill Tarter. (Original broadcast date: March 8, 2013)

We live in a time where the line between fact and fiction is increasingly blurry — where each us can live in a constructed reality. This hour, TED speakers share insights on navigating a world where even the facts are up for debate. TED speakers include historian Deborah Lipstadt, writer Michael Specter, cybersecurity expert Laura Galante, journalist Stephanie Busari, and writer Carrie Poppy.

Many of us are lured by the promise of self-improvement, but find it hard to follow through. In our 100th episode, TED speakers reveal ways to discover our better selves, from simple hacks to deep introspection. TED speakers include entrepreneur Jia Jiang, Headspace co-founder Andy Puddicombe, psychologist Emily Balcetis, technologist Matt Cutts, and New York Times columnist David Brooks.

Success has become synonymous with financial wealth, influence and status. But can we define success in another way — one that welcomes a broader range of accomplishment? It may not be as obvious as you think. In this hour, TED speakers share ideas for what makes us successful. TED speakers include Professor Angela Duckworth, motivational speaker Tony Robbins, HealthTap CEO Ron Gutman, Dirty Jobs host Mike Rowe, and writer Alain de Botton (Original Broadcast Date: November 1, 2013).

In this hour, TED speakers talk about what it takes to become a leader and shake up the status quo. TED speakers include Facebook's Sheryl Sandberg, General Stanley McChrystal, educator Bunker Roy, entrepreneur and writer Seth Godin, and leadership advocate Drew Dudley. (Original broadcast date: January 17, 2014)

Helping others feels good, but why do some go farther than others? This hour, TED speakers explore ideas about altruism — what motivates us to be altruistic, what limits us and do we ever go too far. TED speakers include psychologist Abigail Marsh, clinical psychologist Cheryl Steed, philosopher Peter Singer, and writer Larissa MacFarquhar.

Sinful behavior is human, and nearly impossible to avoid. In this hour, TED speakers talk about the guilty pleasure of behaving badly and the challenge of confronting sin — and avoiding it. TED speakers include psychologist Christopher Ryan, Oklahoma City mayor Mick Cornett, activist Dave Meslin, epidemiologist Gary Slutkin, entrepreneur Nick Hanauer, editor Parul Sehgal, and Jeopardy champion Ken Jennings. (Original broadcast date: February 6, 2015)

When loss, violence or betrayal test our willingness to forgive — how do we do it anyway? This hour, TED speakers explore the challenges and benefits of forgiving others and ourselves. TED speakers include Sue Klebold, Thordis Elva, Tom Stranger, and Elizabeth Lesser.