The Cathedral of the Holy Cross in Boston, USA, offered a prayer service Saturday, on the eve of the 101st anniversary of the Armenian Genocide.

Cardinal Sean P. O’Malley led the ecumenical service that marked the first time the Archdiocese of Boston has formally commemorated the genocide that killed 1.5 million people.

“It is so important that we do not allow the events of the genocide to slip into oblivion,” O’Malley said. “The one and a half million lives are not forgotten.”

O’Malley was joined by church leaders representing a number of Catholic, eastern Orthodox, Christian, and Armenian churches across the eastern United States and Canada.

“We must ask ourselves if the world had responded differently to the Armenian Genocide, could the Holocaust [have been] averted?” he said.

“No civilization can afford to falsify the historical record,” he added. “To do so is perilous.”

Some Armenians said they were grateful for the chance to pray with people of other faiths.

“It was a beautiful ceremony of unity,” said Sona Topjian Frissora, 87. “I can’t tell you how touched I was.”

“It was very memorable for me,” said Lilit Karapetyan. “The most amazing thing is there were people from all religions there.”