Way back in 1969, the Apollo 11 crew carried a silicon disc containing goodwill messages from 73 world leaders. The disc, which is the size of a coin, was left on the Moon by the astronauts. It has two inscriptions: "Goodwill messages from around the world brought to the Moon by the astronauts of Apollo 11," and "From Planet Earth – July 1969."
Curious? Click through the following gallery and read some of the messages astronauts carried to the Moon.