پناهگاه

thumb|The Flak tower|Flakturm at the [[Augarten in Vienna. Flak towers were used as both above-ground bunkers and anti-aircraft gun blockhouses by Nazi Germany]] thumb|The north entrance to the Cheyenne Mountain Complex in [[Colorado, United States]] A bunker is a defensive fortification designed to protect people and valued materials from falling bombs, artillery, or other attacks. Bunkers are almost always underground, in contrast to blockhouses which are mostly above ground. They were used extensively in World War I, World War II, and the Cold War for weapons facilities, command and control