The red, brown and gray hunk is about 70% larger than the next largest piece of Mars found on Earth and represents nearly 7% of all the Martian material currently on this planet, Sotheby’s says. It measures nearly 15 inches by 11 inches by 6 inches.

This Mars rock is up for auction at Sotheby's in New York City this week, which is why it's currently on display in the Upper East Side. As of now, it's expected to sell for between $2 million and $4 million, but it could very well sell for far more.

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.