National Geographic Society has chronicled scientific expeditions, wildlife and world cultures for more than 100 years, amassing 11.5 million photographs and original illustrations.
The Washington-based institution is selling a selection of its archive for the first time. About 240 lots are to be sold at Christie's auction house in New York on Dec. 6. It's expected to bring $3 million.
The archive has 12,000 original pieces of fine art. Highlights in the sale include paintings by N.C. Wyeth and a photo of Admiral Robert Peary's 1908 expedition to the North Pole.
The majority of the works in the sale are by longtime photographers for the magazine.
Proceeds will go for the promotion and preservation of the archive.
Explore further: Ex-Iowa State scientist gets prison for faking HIV research