The collection forty iconic nature photographs will be auctioned by Christie’s first "Green Auction" in New York to mark 40th annual Earth Day.

The collection included photographs of dancing polar bears, a mob of giant tortoises gathering at dawn, bull elephants at dusk and the 1968 image of Earthrise captured by the spaceship Apollo. There is also a stunning photograph of Australian sea lions playing in the sea grass beds.

The money raised from the auction will go to environmental groups, which are trying hard to save Earth from troubles such as global warming.

The International League of Conservation Photographers asked over 100 experts to submit nomination for pictures they considered to be the best in the past hundred years of photography.

Justin Black, the executive director of ILCP said it was very hard for them to choose just 40 pictures for the collection.