When Neil Armstrong and Buzz Aldrin landed on the Moon, they honored soviet cosmonaut Yuri Gagarin by leaving behind one of his medals.
The astronauts left a number of touching troubles behind on the lunar surface as they left: An Apollo 1 mission patch in memory of three US astronauts who died when their command module caught fire during a test in January 1967; two memorial medals of Soviet cosmonauts Vladimir Komarov and Yuri Gagarin (the first man in space), who died in 1967 and 1968 respectively; a memorial bag containing a gold replica of an olive branch; and a silicon message disk carrying goodwill statements from leaders of 73 countries around the world.