40 years ago today, the human race did the most awesome thing it has done to date. Some very brave people went further than anyone ever had, and placed their feet on the surface of somewhere that was not Earth. That we haven't gone further since is disappointing, but I hope we will in my lifetime, because exploration is just something we do, and this world won't hold all of us forever.
Commenters beware: conspiracy theorists will be sent to Mr. Aldrin.
(Also one of our better moments.)