Ice Climbing Up Niagara Falls, Scuba Diving With Orcas, Exploring Mexico's "Snot Caves", Diagnosing the Invisible Impacts of War,

This week, we dodge humpbacks and killer whales in a feeding frenzy, climb up a frozen Niagara Falls, explore Mexico's poisonous "snot caves", diagnose the invisible injuries of American war veterans, and visit Iraq and Syria's frigid refugee camps.