In the United States, it seems obvious that police officers carry guns and are allowed to use them.

In other places, however, this would be considered a provocation and a violation of law.

In Britain, Ireland, Norway, Iceland and New Zealand, officers are unarmed when they are on patrol. Police are only equipped with firearms in special circumstances. It's a strategy that seems to work surprisingly well for these countries. Police officers there have saved lives -- exactly because they were unable to shoot.

"The practice is rooted in tradition and the belief that arming the police with guns engenders more gun violence than it prevents," Guðmundur Oddsson, an assistant professor of sociology at Northern Michigan University, told The Washington Post.