One speck of brain, half a billion connections: Creating the world's most detailed brain map

Scientists have since discovered a whole world within the thymus, a little wad of tissue in your chest. The organ hosts a complex system that trains and equips some of your body's most important fighters against disease.

Gabriel heads out with mud expert Kendall Valentine who gets ankle-deep in the stuff in order to unlock its mysteries.

When you look up at the night sky, it’s easy to think of it as static and permanent, like the stars are painted on up there and never change. But if you look really carefully, sometimes you can catch something dramatic unfolding.

Gabe Spitzer talks to Dr. Hans-Peter Kiem from the Fred Hutch Cancer Center about breakthroughs in gene therapy. He is working on a new way to fight cancer that avoids the grueling process of chemotherapy and instead is administered with a simple shot that sends healthy particles into the body to repair defective cells.

Oncologist Dr. Anthony Back explains how psychedelic drugs can rewire our brains to help people deal with PTSD and stress from terminal illness.