The Fourth Amendment is the part of the Bill of Rights that prohibits "unreasonable searches and seizures." But — what's unreasonable? That question has fueled a century's worth of court rulings that have dramatically expanded the power of individual police officers in the U.S. Today on the show,...

It's hot. A mother works outside, a baby strapped to her back. The two of them breathe in toxic dust, day after day. And they're just two of thousands, cramped so close together it's hard to move, all facing down the mountain of cobalt stone.Cobalt mining is one of the world's most dangerous...