If you believe, they put a Post Office on the Moon https://postalmuseum.si.edu/sites/default/files/pmg_4_4a.jpg https://www.youtube.com/watch?v=LR6SsDMlKrw https://postalmuseum.si.edu/exhibition/one-giant-leap-for-mankind-walking-on-the-moon/canceling-stamps-on-the-moon