Source: James O.Davies [1]

Hey, NASA. Buzz Aldrin has a message for you:

Source: James O.Davies [2]

The iconic astronaut, who was the second person to walk on the moon, visited Stonehenge this week and decided to use it as an opportunity to encourage Mars exploration — in the bluntest way possible. On his Facebook page [3], the social-media-savvy 85-year-old posted the pic and wrote: "While at Stonehenge yesterday I decided to send a message to the cosmos. #GYATM." ICYMI, #GYATM stands for "get your ass to Mars." At least one group is trying. The Mars One group [4] is planning to send 24 volunteers to live and die on Mars.

Check out Buzz on the moon, back in the glory days of space exploration.

Source: NASA/AFP/Getty Images [5]