Today's killings of at least 29 people on the campus of Virginia Tech is among the worst school shootings in U.S. history. Here's a look at some other notable attacks on U.S. campuses:
Oct. 2, 2006: A gunman took about a dozen girls hostage, killing at least three of them, at a one-room Amish schoolhouse in Pennsylvania's Lancaster County, police said. The shooter was among the dead, and a number of people were injured.
Sept. 29, 2006: 15-year-old Eric Hainstock brought two guns to a school in rural Cazenovia, Wis., and fatally shot the principal, a day after the principal gave him a disciplinary warning for having tobacco on school grounds, police said.
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Sept. 27, 2006: Duane Morrison, 53, took six girls hostage at Platte Canyon High School in Bailey, Colo. Morrison, sexually assaulting them and using them as human shields for hours before fatally shooting one girl and killing himself.
Aug. 24, 2006: Christopher Williams, 27, went to an elementaryschool in Essex, Vermont, looking for his ex-girlfriend, a teacher. He couldn't find her and fatally shot one teacher and wounded another, police said. Williams also killed his ex-girlfriend's mother, according to authorities. He shot himself twice in the head ater the rampage and was arrested.
March 21, 2005: Sixteen-year-old Jeff Weise shot and killed five schoolmates, a teacher and an unarmed guard at a high school on the Red Lake Indian Reservation in Minnesota before taking his own life. Weise had earlier killed his grandfather and hisgrandfather's companion.
Nov. 22, 2004: Sixteen-year-old Desmond Keels is accused of fatally shooting one student and wounding three others outside Strawberry Mansion High in Philadelphia. The attack apparently was over a $50 debt in a rap contest. Keels is set to stand trial on murder charges later this month.
April 24, 2003: 14-year-old James Sheets shot and killed the principal in the crowded cafeteria of a junior high school in south-central Pennsylvania, before killing himself.
May 26, 2000: 13-year-old Nathaniel Brazill killed his English teacher on the last day of classes in Lake Worth, Fla., after the teacher refused to let him talk with two girls in his classroom. He was convicted of second-degree murder and is serving a 28-year sentence.
April 20, 1999: Students Eric Harris, 18, and Dylan Klebold, 17, killed 12 students and a teacher and wounded 23 before killing themselves at Columbine High School in Littleton, Colo.
May 21, 1998: Two teenagers were killed and more than 20 people hurt when a teenage boy opened fire at a high school in Springfield, Ore., after killing his parents. Kip Kinkel, 17, was sentenced to nearly 112 years in prison.
May 19, 1998: Three days before his graduation, an honor student opened fire at a high school in Fayetteville, Tenn., killing a classmate who was dating his ex-girlfriend. Jacob Davis, 18, was sentenced to life in prison.
March 24, 1998: Two boys, ages 11 and 13, fired on their Jonesboro, Ark., middle school from nearby woods, killing four girls and a teacher and wounding 10 others. Both boys were later convicted of murder and can be held until age 21.
Dec. 1, 1997: Three students were killed and five wounded at a high school in West Paducah, Ky. Michael Carneal, then 14, later pleaded guilty but mentally ill to murder and is serving life in prison.
Oct. 1, 1997: Sixteen-year-old Luke Woodham of Pearl, Miss., fatally shot two students and wounded seven others after stabbing his mother to death. He was sentenced the following year to three life sentences.
Aug. 15, 1996: Frederick Martin Davidson, 36, a graduate engineering student at San Diego State, is defending his thesis before a faculty committee when he pulls out a handgun and kills three professors.
Nov. 15, 1995: Jamie Rouse kills a student and a teacher at Richland High School in Lynnville, Tenn.
Nov. 1, 1991: Gang Lu, 28, a graduate student in physics from China, reportedly upset because he was passed over for an academic honor, opens fire in two buildings on the University of Iowa campus. Five University of Iowa employees killed, including four members of the physics department, two other people are wounded. The student fatally shoots himself.
May 20, 1988: Armed with three guns, Laurie Wasserman Dann, 30, walked into Hubbard Woods Elementary School in the affluent Chicago suburb of Winnetka, Ill. There she shot one pupil in a washroom before invading a second-grade classroom, where she shot five other pupils, one fatally.
May 4, 1970: Four students were killed and nine wounded by National Guard troops called in to quell anti-war protests on the campus of Kent State University in Ohio.
Aug. 1, 1966: Austin, Texas, Charles Joseph Whitman, a 25-year-old architectural engineering honor student at the University of Texas, climbed to the top of the university's 27-story tower and shot 44 people. The 90-minute shooting rampage was ended when Romero Martinez, an off-duty policeman, climbed the tower and shot Whitman, who died immediately. Authorities later found the bodies of the gunman's mother and his wife at their homes.
Information compiled from various local news sources and wire reports.