Season 23, Episode 11
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.
Aired: 02/23/12Video has closed captioning.