The word Megalodon comes from the Greek words for 'great' (mega) and 'teeth' (odon). This incredibly gigantic shark species became extinct (died off) about 2,000,000 years ago. It is estimated they had a bite force of up to 40,000 pounds per foot!
They were approximately 50 - 70 feet long! Can you imagine? This is as large as a blue whale. (one of the reasons they reached this size was because they hunted whales for food). The largest tooth ever found was about 7 inches long. That is much bigger than a great white shark's tooth.
Because they are extinct, they can no longer be sighted, although their teeth are still found to this day. You can actually buy a Megalodon tooth online. Just search for 'Megalodon tooth for sale' in Google or Bing.
The only proof they lived is the existence of their teeth and vertebra ( back bones ), which are found as fossils. They were found all over the world, from India to Denmark in Europe! The Megalodon is not considered a dinosaur, because it is a fish, not a reptile. Please join me in helping to save the shark by letting people know they are an important part of the food chain and they deserve to be protected like any other living creature and by donating to this pro shark charity - http://gifts.worldwildlife.org/