Olympia

While obviously no one should praise Riefenstahl for the influence her filmmaking brought to Nazi Germany, here her talent, also debatably still under that political lens, is focused on capturing the 1936 Olympic Games in Berlin. Many groundbreaking cinematic techniques were seen here that would only later be more widely used. Perhaps most retrospectively notable is her not including Hitler's reaction to seeing African-American track athlete Jesse Owens set a world-record in the long jump after Germany's Luz Long had just made its own record-setting one. For those not up to watching all three-and-a-half-hours of this, check out the documentary The Wonderful, Horrible Life of Leni Riefenstahl (that includes clips from this and her other work).
For more Olympics see also Kon Ichikawa's documenting of the Summer games of 1964 in Tokyo Olympiad.