Each year human rights activists around the world gather in remembrance of the Jewish lives lost in the Holocaust.
South Korean Christians joined activists this year for a demonstration in Seoul in honor of those victims of Nazi Germany.
They also prayed for Koreans who have perished in North Korean political detention centers.
More than 200,000 prisoners are believed to be held in the camps. Some of them are Christians who were sent to the harsh jails simply for professing faith in Christ.
Kang Cheol Hwan, founding director of the North Korea Strategy Center, suggests South Koreans must express concern if they expect the international community to get involved.
American missionary Robert Park spoke at the rally. North Korean government agents tortured him during his imprisonment in 2010.
He has filed a law suit against the government for violating his human rights.
"North Korea has employed each of the five acts characterized as genocidal," Park explained. "Through executions and state sanctioned murders, the systematic use of torture, state induced mass starvation in political prison camps and elsewhere, forcible abortions and infanticide, and the forcible transfer and enslavement of children."
One North Korean refugee said public executions are continuing in North Korea. He urged international intervention to stop human rights abuses in the country.
Participants marched to the Chinese Embassy in Seoul, demanding that the Chinese government stop ignoring atrocities committed by the North Korean government.
Christian activists also prayed for North Korean prisoners and their families.
"I wept and prayed when I realized how our North Korean brethren would want to speak to our government," college student Lee Hyeongyeop said.
"In Proverbs, it says that we should speak up for those who cannot do so for themselves," he added.
Rally organizers are urging the South Korean church to release a clear statement against the North Korean political prisoner detention camps.