About 65 million years ago, a meteorite about 6 miles (10 kilometers) across crashed into our planet near what is now southern Mexico. The remnant of this collision is an underwater crater more than 100 miles (161 kilometers) across. This asteroid, or comet, carried ten million times more kinetic energy than either the Tunguska or Meteor Crater impactors. The heat from the explosion probably set the air itself on fire for miles around. It threw so much of Earth’s crust into the atmosphere that it blocked most of the Sun’s light for months. As it fell back through the atmosphere, this debris grew very hot as it landed; it probably set almost every tree, bush, and blade of grass it touched on fire. The ecological catastrophe caused by this titanic meteorite strike was most likely the evolutionary blow that finished off the dinosaurs.