A century after Ottoman Turks killed an estimated 1.5 million Armenians, thousands of people from various ethnic communities gathered in Montreal on Sunday to stand up against genocide.

Georges Tsovikian, from the Armenian Genocide Centennial Committee of Canada, said community groups banded together for the march to educate the public about genocides so that they may prevent one from happening in the future.

Dikranuhi Arevian, who was at the rally with her son, told CTV Montreal she attended to honour her Armenian mother. “She suffered so much. I was a child and every night I was waking (up) because my mother wasn’t sleeping, she was crying, crying, crying.”

Montreal Mayor Denis Coderre and other local politicians were among those who made their way from Westmount Park to Place des Arts carrying banners and flags on Sunday afternoon.

Representatives of Montreal’s Holocaust Memorial Centre also marched, and shared images on the social media site Twitter. The museum educates the public about the genocide that killed six million European Jews.

Also in attendance were people holding Ukrainian flags. An estimated seven to 10 million Ukrainians were killed by the Soviet Union in 1932-33 during an intentional famine known as the Holodomor.

Members of the Rwandan community marched too, in remembrance of the 800,000 murdered in the small African nation during 100 horrifying days in 1994.

Cambodian Canadians were also present, to honour the 1.7 million killed under the Khmer Rouge regime in southeast Asia between 1975 and 1979.

Although the governments of Canada, France and Germany recognize the mass killings of Armenians in 1915 as genocide, Turkish President Recep Tayyip Erdogan insists there was no genocide.

The U.S. has resisted labelling the deaths “genocide,” instead opting to call them “atrocities.”

The United Nations International Convention of the Prevention and Punishment of the Crime of Genocide defines genocide as any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group:

(a) Killing members of the group;

(b) Causing serious bodily or mental harm to members of the group;

(c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;

(d) Imposing measures intended to prevent births within the group;

(e) Forcibly transferring children of the group to another group

With a report from CTV Montreal and files from The Associated Press