The Leviathan is believed to have lived 12 million to 13 million years ago, and ultimately became extinct 5 million years ago. Shark Week starts Sunday at 8 p.m. and will end Saturday July 13.

Would the megalodon shark or the Leviathan whale win this epic underwater matchup? Which underwater predator is bigger and who has the strength to take out the enemy? Meloni pays surprise flying ...