Expedition 48 crew members Jeff Williams, Alexey Ovchinin and Oleg Skripochka landed their Soyuz TMA-20M spacecraft in Kazakhstan at 9:13 p.m. EDT after 172 days in space. http://go.nasa.gov/2cztYqC | International Space Station

The disappearance of the Franklin expedition was the worst disaster in polar history. Two ships and 129 crew vanished, and it's taken centuries to piece together the few traces left of this doomed attempt to map the Northwest Passage. Learn more about the ill-fated Franklin expedition and how it's still being explored today: https://on.natgeo.com/4iUxU5v Host: Halley Brown | National Geographic History