Christie’s auction house has put out a rare photo of American astronaut Neil Armstrong on the surface of the moon among thousands of space photos offered for auction.

Christie’s said that more than 2,400 photos documenting the “golden age of space exploration” are the most comprehensive collection of its kind ever to be auctioned.

The most important photo in the auction is the unpublished one of Neil Armstrong, taken during the Apollo 11 mission in 1969 when he became the first human to set foot on the surface of the Moon, accompanied by two crewmates, Buzz Aldrin and MikeCollins.

While stepping on the dirt surface, Armstrong famously said: This is a small step for a man, a giant leap for humanity. “