Over the next two years, Babi Yar became a Nazi burial ground and the remains at least 100,000 bodies, mostly Jews, were found after the war.
The rally marked the 47th anniversary of the killing of more than 100,000 people, mainly Jews, at Babi Yar in the Ukrainian capital.
"Babi Yar was a prelude to the spiritual genocide of the Jewish people of our country," Yuri Sokol, a World War II veteran, told at least 500 people huddled Sunday on a road outside the gates of Moscow's Vostryakov Cemetery.
Babi told police he lived in Angeles with his American wife and two children.