Learn all about mass extinctions, including the history of Earth's five major mass extinctions and their causes: the Ordovician Silurian, Jurassic, Devonian, Triassic and Cretaceous-Paleogene. Scientists say we are now in the middle of the sixth mass extinction, this time caused by human activity - climate change, agriculture, pollution, and over-hunting/poaching are reducing biodiversity. Detailed graphics, diagrams and video images help us learn about interconnectedness, efforts to reverse the problem of mass extinction, the most promising solutions to save Earth's biodiversity, and ways in which you can contribute to these solutions.