A chunk of the Martian surface that made an unlikely voyage to Earth will be available to the highest bidder at Sotheby's auction in New York.

A meteorite that is the largest known piece of Mars on Earth is expected to fetch up to $4 million when it goes up for auction at Sotheby’s on July 16.

Tucked away in a building on the corner of 72nd Street and York Avenue in Lenox Hill, an extraterrestrial marvel sits sturdily on a white pedestal. It's the largest Mars rock on planet Earth — and it turns out its 54-pound (25-kilogram),