The document discusses the Megalodon shark, which lived between 28-1.5 million years ago and was the largest shark that ever lived. The Megalodon could grow up to 50 feet long and weigh over 65 tons, much larger than modern great white sharks. It inhabited oceans worldwide and preyed on whales. Though only fossils remain, analysis shows the Megalodon's massive size and fearsome teeth made it the top predator of its time.