Although this animal is already been found in 1996, this giant Archelon ischyros Turtle fossil of 70 million years old keeps impressing me.

Its “flipper-span” reaches 4.9 meters and its shell 4 meters across. Imagine snorkeling next to this this turtle. Did these ancient already graze on seagrasses? Probably not, it had a leathery carapace, and therefore this turtle seems more related to the present carnivorous leatherback turtle. The original fossile was found in Dakota by  the South Dakota School of Mines and Technology . Thanks to Euroturtle for the link!