Highly acidic Blue Lake sits below the 5,118-foot summit of Maly Semiachik Volcano in Kamchatka. Albert Colman has ventured into this remote region three times since 2005 to study exotic microbes that live in the geothermal pools of nearby Uzon Caldera. The carbon monoxide-producing microbes provide insights into the evolution of Earth's early atmosphere. Photo courtesy of: Albert Colman