The Apollo 11 astronauts left a variety of items on the moon. In addition to the flag, the plaque, and the silicon disk with goodwill statements, they left the item shown above. It is a small replica of an olive branch, described as "less than half a foot in length," a traditional symbol of peace. The gesture was intended to serve as "a wish for peace for all mankind."
Photo: Great Images in NASA, via Fresh Photons.