A riot is a form of civil disorder characterized often by what is thought of as disorganized groups lashing out in a sudden and intense rash of violence against authority, property or people. While individuals may attempt to lead or control a riot, riots are thought to be typically chaotic and exhibit herd behaviour, and usually generated by civil unrest. However, there is a growing body of evidence to suggest that riots are not irrational, herd-like behaviour, but follow inverted social norms.
Riots often occur in reaction to a perceived grievance or out of dissent. Historically, riots have occurred due to poor working or living conditions, government, oppression, taxation or conscription, conflicts between ethnic groups, food supply or religions (race riot, sectarian violence and pogrom), the outcome of a sporting event (football hooliganism) or frustration with legal channels through which to air grievances.
Riots typically involve vandalism and the destruction of private and public property. The specific property to be targeted varies depending on the riot and the inclinations of those involved. Targets can include shops, cars, restaurants, state-owned institutions, and religious buildings.
Some rioters have become quite sophisticated at understanding and withstanding the tactics used by police in such situations. Manuals for successful rioting are available on the internet. These manuals also encourage rioters to get the press involved, as there is more safety with the cameras rolling. There is also more attention. Citizens with video cameras may also have an effect on both rioters and police.
Dealing with riots is an often difficult task for police departments. Police may also use tear gas and CS gas to stop rioters. In some countries riot police have moved to using less-than-lethal methods to control riots, such as shotguns that fire flexible baton rounds to injure or otherwise incapacitate rioters for easy arrest.