March of the Penguins has already earned $66.8 million since its English-language release in June, making the French film by Luc Besson the second highest grossing documentary of all time.
The documentary is also quickly becoming a favourite for an Oscar this year.
This full-length film follows penguins on their way to mate, and follows their reproduction cycle, which is unique in the world. It is comprised of love, drama, courage and adventure in the centre of Antarctica. The film is narrated by Oscar winner Morgan Freeman.
The highest grossing documentary of all time is the film Fahrenheit 9/11 by Michael Moore.