Oceanographer Kate Stafford lowers us into the sonically rich depths of the Arctic Ocean, where ice groans, whales sing to communicate over vast distances -- and climate change and human noise threaten to alter the environment in ways we don't understand. Learn more about why this underwater soundscape matters and what we might do to protect it.

"I sell dreams, and I peddle love to millions of people," says Shah Rukh Khan, Bollywood's biggest star. In this charming, funny talk, Khan traces the arc of his life, showcases a few of his famous dance moves and shares hard-earned wisdom from a life spent in the spotlight.

How can humans be so compassionate and altruistic -- and also so brutal and violent? To understand why we do what we do, neuroscientist Robert Sapolsky looks at extreme context, examining actions on timescales from seconds to millions of years before they occurred. In this fascinating talk, he shares his cutting edge research into the biology that drives our worst and best behaviors.

Carolyn Jones spent five years interviewing, photographing and filming nurses across America, traveling to places dealing with some of the nation's biggest public health issues. She shares personal stories of unwavering dedication in this celebration of the everyday heroes who work at the front lines of health care.

In the US, most kids have a very long summer break, during which they forget an awful lot of what they learned during the school year. This "summer slump" affects kids from low-income neighborhoods most, setting them back almost three months. TED Fellow Karim Abouelnaga has a plan to reverse this learning loss. Learn how he's helping kids improve their chances for a brighter future.

When stress got to be too much for TED Fellow Sangu Delle, he had to confront his own deep prejudice: that men shouldn't take care of their mental health. In a personal talk, Delle shares how he learned to handle anxiety in a society that's uncomfortable with emotions. As he says: "Being honest about how we feel doesn't make us weak -- it makes us human."

Hacking, fake news, information bubbles ... all these and more have become part of the vernacular in recent years. But as cyberspace analyst Laura Galante describes in this alarming talk, the real target of anyone looking to influence geopolitics is dastardly simple: it's you.

"There are facts, there are opinions, and there are lies," says historian Deborah Lipstadt, telling the remarkable story of her research into Holocaust deniers -- and their deliberate distortion of history. Lipstadt encourages us all to go on the offensive against those who assault the truth and facts. "Truth is not relative," she says.

Elon Musk discusses his new project digging tunnels under LA, the latest from Tesla and SpaceX and his motivation for building a future on Mars in conversation with TED's Head Curator, Chris Anderson.

Alzheimer's doesn't have to be your brain's destiny, says neuroscientist and author of "Still Alice," Lisa Genova. She shares the latest science investigating the disease -- and some promising research on what each of us can do to build an Alzheimer's-resistant brain.