Yellowstone national park is the most extensive geothermal area on earth, with more geysers than the rest of the world put together. In its springs, different species of microorganisms live according to the temperature of the water, and provide a glimpse into the conditions that first spawned life on this planet.

Originally released by BBC Worldwide Learning, 2010. Streaming video file encoded with permission for digital streaming by Infobase on April 18, 2015.

Thermal secrets (3:00); .