The Viking 1 orbiter brought some surprised attention to the Cydonia region of Mars in 1976 when its cameras discovered what appeared to be an enigmatic face staring up into the heavens.

The “face on Mars” has since been explained as an optical illusion, but it recalls a project conceived 30 years earlier by the American artist Isamu Noguchi. Sculpture to Be Seen From Mars, below, was proposed as a massive earthwork to be constructed in “some unwanted area,” perhaps a desert, at an enormous scale, so that the nose would be 1 mile long. When seen from space, the face would show that a civilized life form had once existed on Earth. Noguchi had been embittered by his experiences as a Japanese-American during World War II and the development of atomic weapons; he had originally called the piece Memorial to Man.

If those two don’t have enough to talk about, there’s a newcomer to join them: In 2013, face recognition software discovered the image below in a photo of the moon’s south pole taken by NASA’s Lunar Reconnaissance Orbiter. Who’s next?