oceansorbitingblackholes:

Throughout the extensive Luftwaffe bombing of Britain it was common for Londoners to spontaneously seek shelter in the London Undergound. During the Blitz (which lasted from the seventh of September 1940 until the 10 May 1941) the city of London was bombed for 76 consecutive nights. More than 20,000 died. The government however rejected their use as shelters, stating as early as 1939 that Underground stations must be locked during raids. This lead to consistent clashes between those seeking shelter and Underground officials.  Regularly more than 100,000 would sleep in the Underground each night. In November 1940 cabinet officially recognised the use of the Underground for protection and proceeded to construct shelter space for over 80,000. Ironically these shelters were constructed following the heaviest of the raids and were never used. The largest recorded mass in the Underground was on the night of the 27th of September 1940 when over 177,000 slept in the tunnel systems currently connecting greater London.