![dek](https://content.time.com/time/photoessays/2009/top10_moon/outer_space_treaty.jpg)
The U.S. joined with the Soviet Union in 1967 to create the Outer Space Treaty, declaring the moon subject to a similar set of rules as those used to govern international waters on Earth. The treaty, which 97 other countries are now party to, makes the moon off-limits for military purposes, keeping countries from ever constructing bases or weaponry on the lunar surface.