Which animal is the largest in the world?

The blue whale is the largest animal ever known to exist, even bigger than the biggest dinosaurs. Its huge body houses similarly massive organs, and it survives largely by filtering tiny shrimp-like krill from the water.

An elephant is the largest land animal alive today, but far smaller than a blue whale, since living in water lets whales grow bigger than any land animal's legs could support. A great white shark is a powerful predator, still much smaller than a blue whale.

A blue whale's heart alone weighs roughly as much as two grown adults combined.