Concerts have sometimes been a target for those wanting to inflict harm on a large number of people, and the overnight mass shooting at a country music festival in Las Vegas comes as an example.
Is it the open environment? Lack of concert by spectators? Investigators are looking for answers as to why a mass shooter wanted to harm so many random people.
Sunday's shooting in Las Vegas, in which dozens were killed and hundreds hurt, marks the deadliest such event in recorded U.S. history. The shooting took place at an outdoor festival where nearly 30,000 people had gathered to hear headliner Jason Aldean perform.
A 64-year-old Nevada man, Stephen Paddock, opened fire from the 32nd floor of the Mandalay Bay hotel. Police believe Paddock killed himself before law enforcement entered the room, police said.
Here is a look at past intentional acts of violence at concerts around the world:
Manchester Arena bombing, May 22, 2017
An explosion in the foyer of Manchester Arena at the end of an Ariana Grande performance killed 22 people. The bombing took place as attendees were exiting the concert, and took place in an area just outside of security screenings. Many of those killed or wounded were children. The attack forced Grande to cancel the rest of her tour. She did, however, perform at a benefit concert weeks later in Manchester.
Le Bataclan shooting, Nov. 13, 2015
The Eagles of Death Metal concert was one of several targets in the Paris area on Nov. 13, 2015, in an attack that killed 130 people. Of the 130 killed, 89 died at the Bataclan theatre. The Islamic State group claimed responsibility for one of the most coordinated terrorist attacks in European history.
Dimebag Darrell shooting, Dec. 8, 2004
Four people were killed, including former Pantera frontman Darrell Lance Abbott aka Dimebag Darrell, at the Alrosa Villa nightclub in Columbus, Ohio. The shooter, Nathan Gale, a 25-year-old former Marine, was upset about Pantera breaking up. Gale was killed when a Columbus Police Officer fired into Gale, while Gale attempted to reload and fire on the crowd.