A 54-pound (25-kilogram) rock. Estimated auction price: $2 million to $4 million. Why so expensive? It's the largest piece of ...

Sotheby's is putting some rare items up for auction, including what it calls the largest piece of Mars ever found on Earth.

The auction house Sotheby’s has offered a new way to get a piece of Mars without entrusting your life to Elon Musk, who has pledged to send people to Mars by 2029: Buying a piece of it instead. A ...