During World War II, many countries built shelters to protect civilians from air raids and bombings. These shelters varied in design, ranging from simple backyard structures to large underground bunkers. Common types included Anderson shelters, which were made of corrugated steel and could be assembled in gardens, and Morrison shelters, designed for indoor use, providing safety during attacks. Governments encouraged citizens to use these shelters during air raids, often providing instructions on how to build and maintain them. In cities like London, the extensive use of Tube stations as makeshift shelters helped protect thousands from the dangers of aerial bombardment.