Explained

E1. The Racial Wealth Gap

Cory Booker and others discuss how slavery, housing discrimination and centuries of inequality have compounded to create a racial wealth gap.

★ 7.6

E2. Designer DNA

Scientific feat or terrifying social experiment? Specialists in the field discuss the high stakes and ethical controversies of gene editing.

★ 7.8

E3. Monogamy

What do biology, human history and the promiscuity of bonobos reveal about monogamy? Experts and everyday couples weigh in on shifting cultural norms.

★ 6.3

E4. K-Pop

Elaborate music videos, adoring fans, killer choreography. Learn about the global music phenomenon from South Korea that goes beyond "Gangnam Style."

★ 7.8

E5. Cryptocurrency

Cryptocurrency has made people billionaires, but is digital cash the next revolution? Learn about this anonymous currency and how it's coveted.

★ 7.5

E6. Why Diets Fail

Atkins. Paleo. Keto. Do any work in the long term? Experts look at marketing, food environments and genes to explain why diets are often unsuccessful.

★ 7.4