Season 23, Episode 11
Video duration: 28:10Video has closed captioning.
Biscuit Fire 10 Years Later - 10 years after the Biscuit fire, scientists have uncovered a treasure trove of surprises. Balloon Archaeology - Balloon archaeology provides a whole new view of mysterious circles now found in Oregon. Collier Glacier - 100 years of photos show the dramatic retreat of Collier Glacier.