EDITOR'S NOTE (GRAPHIC WARNING): This story contains a photograph of a young boy who died, an image readers may find distressing. The image is lower down in the story.

The world’s attention is on the international migrant crisis this week, in large part due to a single powerful image of dead Syrian boy on a Turkish beach.

Canada’s federal party leaders addressed the death of Alan Kurdi, 3, while campaigning Thursday.

Conservative Leader Stephen Harper told reporters he and his wife Laureen had reacted like any other parent might. “The first thing that crossed our mind was remembering our own son Ben at that age,” he said.

NDP Leader Tom Mulcair, meanwhile, said it reminded him of ‘Napalm Girl,’ the screaming child photographed after a U.S. napalm attack during the Vietnam War. “Certain images define an era,” he said. “It’s unbearable to see.”

Kenny Irby, who chaired the 2007 Pulitzer Prize photography categories, and is now a senior faculty member at The Poynter Institute in Florida, said that the photo of Alan Kurdi “depicts a reality that, for whatever reason, has been neglected.”

“Immigration has been a story for a long time,” Irby explained. “It’s the death of a child that looks like any other child -- the human reality of the little sneakers, the little clothes, (that) makes it feel like it could be anywhere.”

Kurid said it’s a reminder of the power of photojournalism to change history.

“There’s no denying the fact that there have been single photographs that have moved the hearts and minds of people in the world to action, where before there had been inaction, negligence or denial,” Irby added.

Here are four other moments in history where a single photograph seemed to grab the world’s attention all at once.

Tank Man: On June 5, 1989, Associated Press reporter Jeff Widener captured the image of a single man attempting to block a row of tanks headed to Tiananmen Square in Beijing, where the Chinese government had killed hundreds, perhaps thousands, of pro-democracy protesters a day earlier. Irby says that photo “spoke to an individual against their country.”

Tiananmen Square's tank man

Black Power: After winning medals in the 200-metre race at the Mexico City Summer Olympics on Oct. 16, 1968, American sprinters Tommie Smith and John Carlos mounted the podium and raised their hands skyward in solidarity with the civil rights movement. “People still look back to that image … as a trigger,” Irby said. “It moved the movement forward.” (The Associated Press)

1968 Olympics black power salute

Oka Crisis: Canadian Press photographer Shaney Komulainen snapped an iconic image of Canadian soldier Patrick Cloutier and First Nations activist Brad Laroque standing face to face on Sept. 1, 1990, which was part-way through a 78-day standoff over disputed land in Oka, Que. UBC sociologist Rima Wilkes has written that the image was a “turning point” for many Indigenous people because a small number of protesters “stood up to the army.”

Oka crisis famous photo

Wait for me, Daddy: Private Jack Bernard from of the Duke of Connaught's Own Rifles was caught by Vancouver Daily Province photographer Claude P. Detloff reaching out to his five-year-old son, Warren Bernard, as he left B.C. in 1940 to fight in the Second World War. The photo came to symbolize the sacrifice Canadian families made during the deadly conflict.

Wait for me, Daddy

Migrant Crisis: Three-year-old Alan Kurdi, his five-year-old brother Galib, and their mother, Rehan, drowned as they attempted to cross from Turkey into Greece on Wednesday. A photo of Alan’s lifeless body on a Turkish beach has drawn attention to the hundreds of thousands of people who have attempted to find safety in Europe by crossing the Mediterranean this year, after fleeing war-torn countries like Syria, Eritrea, Iraq and Afghanistan. (AP Photo/DHA)

Alan Kurdi child migrant boy