With a leg span of up to 12 feet (3.8 meters), the Japanese spider crab (Macrocheira kaempferi) is the biggest crab in the world. It lives in the Pacific Ocean's mesopelagic (twilight) zone at depths ...

Creatures that live in deep sea environments, such as this sea angel, are quite unlike the beings we're accustomed to seeing on land. Yiming Chen / Getty Images ...

What is the biggest animal in the world? It is worth noting that the largest living animals in the world today aren’t land animals, because on land they must struggle against the forces of gravity to ...