Families of Holocaust survivors paid tribute Sunday to thousands of Greek Jews killed by the Nazis during WWII. "It is our duty to help future generations by promoting values such as respect for human rights, freedom and solidarity and keeping away from hate and intolerance," said David Saltiel, the president of the Jewish community in Thessaloniki. Nearly 90 percent of Greece's 80,000 Jews were wiped out during the Holocaust. Most of them had lived in this port city once known as the pearl of Israel. Some 1,500 Greek Jews live in Thessaloniki today. "It created a dent in the city's demography with whole neighborhoods losing their inhabitants," said Zanet Battinou, Director of the Jewish Museum in Athens. "These are communities that will not recover from this". Many Greek Jews trace their origins back to Sephardic ancestors that took refuge in Thessaloniki after being driven out of Spain in 1492. The Greek government said International Holocaust Day - formally marked on Saturday - should serve as a strong warning against the danger of racism and against similar atrocities ever taking place again. "The right to remember and educate generations to come on the Holocaust is evident and nonnegotiable," Foreign Minister Dora Bakoyannis said Friday. "It constitutes an underlying condition for avoiding similar genocides in the future" A vigil was held on Sunday at the city's Holocaust monument, followed by speeches by the government officials and the head of Thessaloniki's Jewish community. Battinou said Holocaust remembrance remains important, to remind Greeks "there are no solutions so bleak that we cannot do the right thing." She added: "We must always find the strength to do what is right (as) values such as democracy and freedom can easily slip from our fingers." Greece was occupied by Nazi Germany from 1941 to 1944. The Greek national resistance took on the Jewish cause, organizing safety routes up to the mountains and out to the Middle East. January 27, the Holocaust Remembrance Day, marks the day in 1945 when the Auschwitz-Birkenau concentration camp - where more than 1.5 million people perished, most of them Jewish - was liberated by Soviet troops.