Cave diver Jill Heinerth explores the hidden underground waterways coursing through our planet. Working with biologists, climatologists and archaeologists, Heinerth unravels the mysteries of the life-forms that inhabit some of the earth's most remote places and helps researchers unlock the history of climate change. In this short talk, take a dive below the waves and explore the wonders of inner space.

For architect Ole Scheeren, the people who live and work inside a building are as much a part of that building as concrete, steel and glass. He asks: Can architecture be about collaboration and storytelling instead of the isolation and hierarchy of a typical skyscraper? Visit five of Scheeren's buildings -- from a twisted tower in China to a floating cinema in the ocean in Thailand -- and learn the stories behind them.

Wael Ghonim helped touch off the Arab Spring in his home of Egypt ... by setting up a simple Facebook page. As he reveals, once the revolution spilled onto the streets, it turned from hopeful to messy, then ugly and heartbreaking. And social media followed suit. What was once a place for crowdsourcing, engaging and sharing became a polarized battleground. Ghonim asks: What can we do about online behavior now? How can we use the Internet and social media to create civility and reasoned argument?

We've invested so much in police departments as protectors that we have forgotten what it means to serve our communities, says Baltimore Police officer Lt. Colonel Melvin Russell. It's led to coldness and callousness, and it's dehumanized the police force. After taking over as district commander in one of Baltimore's toughest neighborhoods, Russell instituted a series of reforms aimed at winning back the trust of the community and lowering the violent crime rate. "Law enforcement is in a crisis," he says.