Air Raid Vault Uses Chain of Gas Masks 1939
This shelter manages to have a macabre irony on two levels - first, Winkel shelters looked like missiles, and second, this one now forms part of a kids playground.
Many of London's Underground stations were used as shelters, since unlike most subways systems the London Tube network is tunneled deep rather than cut and covered.
Used by firewatchers in the UK during WWII.
Until recently Swiss law dictated that practically all buildings have an underground shelter complete with blast doors and resulting in suburban dwellings build with typical Swiss over spec, including a shelter which would cost more than the average US family house, to build.
These arty types have converted one into a zero star hotel.