I knew this had to be the infamous megalodon at the National Museum of Natural History when I gazed upon it. This was probably the largest shark to ever live, and since it died out about somewhere between 2.5 to 5 million years ago, it actually is kind of a recent creature to the history of the Earth.
Here's us to scale. Yeah...it doesn't even need teeth for us. Could you imagine being in the water if a creature like this still existed? Regular sharks are bad enough to scare someone.