Bunker

The term "bunker" in its military sense was first recorded in English in 1939, initially referring to German fortifications. 

Schindler-Bunker, a Swiss mini-bunker from WWII Flickr

The walls of some World War II artillery bunkers were up to 3.5 meters (11 feet) thick to withstand heavy bombardment.

Winston Churchill’s secret bunker was in Neasden. It was so horrible he only went there once.

Hitler's "Wolf's Lair" (Wolfsschanze) on the Eastern Front consisted of numerous interconnected trench bunkers.

The man who designed Saddam Hussein's bunker was the grandson of the woman who designed Adolf Hitler's bunker.

During the Cold War, the Diefenbunker in Canada could house 565 people for a month as part of the government's continuity plan.

Fearing invasion during the Cold War, Albania’s leader Enver Hoxha forced his country to build 750.000 bunkers in a process called "bunkerization. Today, many of those bunkers have been converted into a variety of uses, like turning them into pizzerias, espresso bars and makeshift bars.

Bunkers in Albania By Marc Morell

The Bunk'Art in Albania, originally built for the dictator, is now a museum and art cente

The huge underground secret bunker located at Mt. Weather, Virginia, intended to house the Government in case of a nuclear war, was disclosed to the public when TWA Flight 514 slammed into the mountain close to the entrance of the base in 1974.

Nuclear bunkers are designed to cope with both the initial blast wave and the subsequent underpressure that lasts for several seconds after the shock wave passes4.

Bunker doors must be at least as strong as the walls to provide adequate protection.

The "Gravel Gertie" bunker at the Pantex plant in Texas was specifically built to contain radioactive materials during nuclear warhead assembly/

The Sonnenberg bunker in Switzerland was formerly the world's largest public fallout shelter, 

Some Swiss bunkers have been converted into tourist attractions, housing hotels and museums.

A former top-secret bunker in Latvia now serves as a museum displaying Soviet memorabilia.