For the first time, one of American history's greatest undiscovered artifacts is revealed -- an 1865 image of Abraham Lincoln on his deathbed. Now, Professor Whitny Braun is on a mission to determine the authenticity of the photo.

Eleven lives were lost after deadly weather conditions struck Mt. Everest in the spring of 2019. Now, the world's most experienced climbers reveal what it's like to survive those conditions and what it would take to prevent another similar tragedy.