Fossil fuels are made from the remains of extinct organisms that have been exposed to millions of years of heat and pressure. But in the case of coal, these organisms consisted largely of some downright bizarre plants that once covered the Earth, from Colorado to China.

Originally released by Knowledgemotion, 2017. Streaming video file encoded with permission for digital streaming by Infobase on February 21, 2020.

History's Most Powerful Plants (5:47); .