Explanation: During the Cold War, the USA and USSR competed in many areas to 'prove' whose system was superior. One such area was the so-called "Space Race", wherein both sides competed for prestigious 'first achievements' in space. The USSR put up the first satellites and people into space, but the USA was the first to land people on the moon.
... for some reason, an enduring minority in the US has continued to believe that it was a 'hoax' and 'faked', for gods only know what reason. The USSR, by contrast, was watching the whole affair very closely - once it was apparent that the mission was a success, genuine congratulations were extended, and samples of moon rocks were shared with USSR when the mission touched down. After all, the competition was about the prestige - science knows no borders*!
*unless it has some military application, at which point it becomes classified