Police officers are employees of a law enforcement agency in their country, region, or city. Often called policemen, policewomen, or constables, police officers swear an oath to protect and serve the citizens they represent. They are warranted by the government to enforce the law by arresting criminals and detecting and preventing crimes. Because keeping the peace is a primary need of society, police officers have been around since civilization began. They are usually viewed as heroes within their communities due to the often dangerous situations they encounter in service to the public.