In 1936 Owens arrived in Berlin to compete for the United States in the Summer Olympics. Adolf Hitler was using the games to show the world a resurgent Nazi Germany. He and other government officials had high hopes German athletes would dominate the games with victories (the German athletes did indeed achieve a top of the table medal haul). Meanwhile, Nazi propaganda promoted concepts of "Aryan racial superiority" and depicted ethnic Africans as inferior. Owens surprised many by winning four gold medals and consequently shattered Hitler's preached values.
This goes to show that some of the most successful methods of breaching oppressive regimes have been through actions rather than words, as is the case with the black liberation movement of Jazz.
It may have been possible for Hitler to limit black people's rights but as is clearly demonstrated here, no matter how many material possessions you might take away, it is not possible to extract a persons skills or memories which are some of the most powerful and invisible weapons of them all.