In the history of Earth, at least five massive extinctions have been documented. The most recent extinction occurred 65 million years ago, at the end of the Cretaceous, (wiping out the “Jurassic Park”, in other words, wiping out the dinosaurs, and many other species. The causes of the past extinctions were most likely related to dramatic climate changes caused by geological activity. Various researchers consider that current impacts of human activities are leading to a sixth massive extinction.