When a huge meteorite crashed into the earth 66 million years ago and caused the disappearance of the dinosaurs, some of the planet’s tiniest species survived the cataclysm, and—against all odds—eventually became some of the greatest giants to ever roam the earth. From the poles of the planet to the belly of the equator, this documentary sheds new light on four giant animals that are still a great mystery to science today: the Titanoboa snake, the Megalodon shark, the giant rhinoceros and the giant sloth.