What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.

Racism isn't always obvious, but it can be found almost everywhere. This hour, TED speakers explore the effects of everyday and systemic racism in America—and how we can work to defeat it. Guests include authors Brittney Cooper and Monique Morris, journalism professor Pat Ferrucci, clinical psychologist Howard Stevenson, and anti-racism educator Travis Jones.

Why do many of us hate, even fear math? Why are we convinced we're bad at it? This hour, TED speakers explore the myths we tell ourselves and how changing our approach can unlock the beauty of math. Guests include budgeting specialist Phylecia Jones, mathematician and educator Dan Finkel, math teacher Eddie Woo, educator Masha Gershman, and radio personality and eternal math nerd Adam Spencer.

What makes someone lucky? Can luck be controlled, is it random, or is it based on something else entirely? This hour, TED speakers explore ideas about why some people seem so much luckier than others. Guests include former professional poker player Liv Boeree, professor of entrepreneurship Tina Seelig, community activist Amy Hunter, journalist Mark Sutcliffe, and youth services advocate Eshauna Smith.

How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.

The Me Too movement has changed the way we think and talk about gender discrimination. This hour, TED speakers explore how the conversation has moved beyond a hashtag, and where we go from here. Guests include Me Too movement founder Tarana Burke, actor and activist Ashley Judd, writer Laura Bates, and anti-sexism educator Jackson Katz.