over. august of 2006, a couple dozen people are making their way to the rocks near the glacier. it's a warm, summer day. as they gather to take photos of the magnificent ice fall, a large piece falls off and falls into the water. the spectators are likely entranced by the glacier, thrilled by the opportunity to see it move. but the tourists are unaware that the small break in the ice signals a much larger crash to come. >> it's hypnotizing. you don't realize the danger of being there. >> marco is a new york based glaciologist. >> the power of a glacier is very, very strong. all the energy is moving slowly. >> marco's work takes him to the planet's moat remote environments, where secrets of the earth's atmosphere are hidden inside air pockets in the ice.