Megalodon, meaning "big tooth," lived approximately 28 to 1.5 million years ago during the Cenozoic Era. Fossil remains suggest that these giant sharks reached a maximum length of 46-59 feet, and scientists believe that it looked like a stockier version of the Great White Shark.
According to accounts from the Renaissance, gigantic triangular fossils of teeth found in rock were once believed to be the petrified tongues of dragons and snakes. Danish naturalist, Nicolaus Steno, corrected this interpretation in 1667 when he recognized these fossils as shark teeth, and produced a depiction of a shark's head bearing such teeth. He described his findings in his book The Head of a Shark Dissected.