When the Second World broke out in Europe, and London became the prime bombing target, people began to pour into the platforms of the London Underground —the city’s subway system— every night to escape the nightly bombings of the 1940 London Blitz. As these underground sanctuaries became increasingly crowded, the British government decided to construct proper air raid shelters far below the ground. The idea was to build ten shelters and place them slightly below and near existing subway stations with the intention that these newly built tunnels will be eventually absorbed into the Underground once the war was over.

The Stockwell deep level shelter entrance in London, now decorated as a war memorial. Photo credit: David Iliff/Wikimedia