A face on Mars
A face on Mars This image, taken by NASA's Viking 1 orbiter and released on 25 July 1976, captured the public's attention because of a feature that looks very much like a human face. Further observations confirmed that this is in fact just a hill in Mars' Cydonia region. The human brain is wired to identify faces, even when they aren't there. NASA/JPL

"We're changing the world. Are you in?"
- CEO Bill Nye

Sign up for email updates