Timeline

Oct. 2, 2006
Amish schoolhouse, Nickel Mines, Pa.

Charles Carl Roberts, a 32-year-old milk-truck driver and father of three children, walks into a single-room Amish schoolhouse in the village of Paradise near Nickel Mines and kills a number of children. The young victims - all girls between the ages of 6 and 13- are lined up against a blackboard and shot execution-style, police report. Earlier, Roberts had ordered the 15 boys in the class, as well as several women with younger children, to go free.

Negotiations with police fail as Roberts turns the gun on himself and commits suicide. Police later speculate Roberts had been nursing a 20-year "grudge" and was exacting revenge for an incident that happened to him when he was 12 years old, but no other details are released to explain why he opened fire. Roberts was not a member of the Amish community he targeted. By the next morning, there is a death toll of five girls, after a seven-year-old and a nine-year-old passed away overnight at different hospitals. Five other girls remained in critical condition.

Sept. 13, 2006
Dawson College: Montreal

An injured person is wheeled away from Montreal's Ecole Polytechnique on Dec. 6, 1989 after gunman Marc Lepine opened fire at the university. Rifle fire echoing down the halls of a Montreal college on Wednesday conjured instant memories of Lepine’s horrific rampage almost 17 years ago. (Shaney Komulainen/Canadian Press)

A young man opens fire outside Dawson College, a CEGEP serving about 10,000 students in downtown Montreal, and then continues the rampage inside the school. Witnesses describe seeing a tall skinny youth with a Mohawk haircut walk into the cafeteria shortly before 1 p.m. ET carrying a large gun. The shooter, Kimveer Gill, 25, lived in a borough of Laval north of Montreal. He killed himself in a confrontation with police inside the school. One woman is killed, 18-year-old Anastasia DeSousa, and 19 people are wounded, at least six critically. They range in age from 17 to 48, according to police.

• In depth: Dawson College
• CBC story: Dawson student remembered for penchant for pink ( Sept. 15, 2006)

March 21, 2005:
Red Lake High School, Red Lake reservation, Minn.

Jeffrey Weise, a 16-year-old student, opens fire at a high school on the Red Lake reservation in northern Minnesota, about 120 kilometres south of the Canadian border. He kills seven people at Red Lake High School: five students, a teacher and a security guard. He also slays two family members. He dies after the shooting.

Sept. 1, 2004:
School Number One, Beslan, Russia

Chechen militants take over School Number One in Beslan, Russia, where more than 1,100 students, teachers and parents become hostages. Three days later, two explosions rock the school and Russian forces launch a chaotic rescue. In total, 333 hostages die.

April 26, 2002:
Johann Gutenberg Gymnasium, Erfurt, Germany

A former student at Johann Gutenberg Gymnasium in Erfurt, Germany, kills 16 people before turning the gun on himself. Most of Robert Steinhauser's victims are teachers.

April 28, 1999:
W. R. Myers High School, Taber, Alta.

A 14-year-old boy opens fire with a .22-calibre rifle inside W. R. Myers High School in Taber, an Alberta town about 200 kilometres southeast of Calgary. The boy, who can't be named because of his age at the time of the crime, kills student Jason Lang, 17. Another student, Shane Christmas, 17, is wounded, but recovers from his injuries. The shooting takes place a week after the Columbine High School massacre.

• In depth: Taber tragedy

April 20, 1999:
Columbine High School, Near Littleton, Colo.

Two teenage students arrive at Columbine High School near Littleton, Colo., wearing long black dusters, the trademark of a small clique of outsiders at the school known as the Trenchcoat Mafia. Although Eric Harris, 17, and Dylan Klebold, 18, weren't inside members of the clique, they adopt its look as they carry in an arsenal that includes a semi-automatic rifle, a semi-automatic handgun and a sawed-off shotgun. They first open fire in the school cafeteria and ultimately kill 12 students and a teacher, as well as wounding 24 others. Then they kill themselves. The shooting shocks the world for its ferocity, sparking debates on gun control, school security, goth culture and video-gaming culture. Police in several U.S. towns report foiling attempts to emulate the massacre.

March 24, 1998:
Westside Middle School, Near Jonesboro, Ark.

Two boys go on a rampage at Westside Middle School near northwestern Jonesboro in Arkansas, dressed in camouflaged clothes and carrying seven firearms stolen from one of the boys' grandfathers — two semi-automatic rifles, one bolt-action rifle and four handguns. Mitchell Johnson, 10 and Andrew Golden, 8, trigger a false fire alarm and open fire from the woods when everyone pours out of the school. They kill four female students and a teacher, as well as wounding nine other students and a teacher. They are sentenced to be confined in a youth facility until their 21st birthdays. In 2005, the two boys are released and their records wiped clean.

Dec. 1, 1997:
Heath High School, West Paducah, Ky.

Michael Carneal, a 14-year-old student at Heath High School in West Paducah, Ky., opens fire shortly after arriving at school, targeting a youth prayer group. Eight people are hit and three die. Carneal surrenders to the school principal. He is sentenced to three concurrent life sentences for murder and an additional 120 years for five counts of attempted murder and burglary.

March 13, 1996:
Dunblane Primary School, Dunblane, Scotland

A 43-year-old unemployed former storeowner, Thomas Hamilton, cuts the telephone lines to Dunblane Primary School in central Scotland and enters, armed with two pistols, two revolvers and more than 700 cartridges. He begins shooting in the school gymnasium, killing a teacher and 16 children many of them under the age of six. Subsequent investigation found that Hamilton had been a former Scout leader who had questioned by police several times after complaints about his behaviour around young children. The controversy surrounding the tragedy led to tighter gun controls.

Dec. 6, 1989:
L'École Polytechnique, Montreal

Marc Lépine, 25, walks into a classroom at Montreal's l'École Polytechnique engineering school, separates the men from the women and tells the men to leave. Then he begins shooting from a semi-automatic military weapon, shouting "I want women" as he roams the school's floors. Lépine kills 13 female students and a college employee, and injures 13 others before committing suicide. He had purchased a semi-automatic, a Ruger Mini-14, to carry out his assault. The ease with which he had acquired it and carried out the assault leads to the creation of pressure groups, which eventually forces the federal government to set up a national gun control registry.

• CBC Archives: Montreal massacre
• In depth: Gun control