Antarctica (or the South Pole) is a frozen continent at the bottom of our world.
Despite be a unvivible environment, it's inhabitated by penguins, killer whales, sealgulls and leopard seals.
It was briefly seen in Madagascar, where Skipper and the Penguins reach their true destination, until they think it's too cold for them.
A secret UFO outpost was one location in Antarctica, in the beginning of Monsters Vs. Aliens.
In Rise of the Guardians, Jack Frost after accidently betraying the Guardians flies in exile to there, until Pitch comes along, and asks him if he can work for him.