In 1938, with the outbreak of World War II on the horizon, Sir John Anderson was placed in charge of air-raid preparations in Britain. He commissioned engineers to design a cheap and simple shelter which could be distributed to the population.

The result: the Anderson Shelter.

Six feet tall, 6.5 feet long, and 4.5 feet wide, the corrugated metal shelters were a snug fit for a family of six. They were buried four feet under owners' yards, their arched roofs covered with a layer of soil.

The shelters were distributed for free to poorer residents. Wealthier residents could purchase one for a small fee.

Many chose to incorporate the shelters into their gardens, planting vegetables and flowers on top of them. Residents even held competitions for prettiest shelter.

By the time the Blitz began, over 2 million Anderson shelters had been erected.