![Visitors look at an air supply tunnel in Lucerne's Sonnenberg nuclear fallout shelter September 12, 2006, built from 1971 to 1976, which was to be a safe haven for 20,000 local residents Visitors look at an air supply tunnel in Lucerne's Sonnenberg nuclear fallout shelter September 12, 2006, built from 1971 to 1976, which was to be a safe haven for 20,000 local residents](https://c8.alamy.com/comp/2D20D04/visitors-look-at-an-air-supply-tunnel-in-lucernes-sonnenberg-nuclear-fallout-shelter-september-12-2006-built-from-1971-to-1976-which-was-to-be-a-safe-haven-for-20000-local-residents-in-case-of-emergency-the-shelter-one-of-the-worlds-biggest-is-about-to-be-closed-down-as-the-nature-of-threats-shifts-from-a-nuclear-cataclysm-to-terror-attacks-on-civilians-in-the-post-cold-war-period-picture-taken-september-12-2006-to-match-feature-swiss-nuclear-bunker-reuterssebastian-derungs-switzerland-2D20D04.jpg)
Visitors look at an air supply tunnel in Lucerne's Sonnenberg nuclear fallout shelter September 12, 2006, built from 1971 to 1976, which was to be a safe haven for 20,000 local residents
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Emergency Air: For Shelter-in-Place Preppers and Home-Built Bunkers: Bohan, F.J.: 9781983713934: Amazon.com: Books
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air for underground shelter - Google Search | Underground shelter, Underground greenhouse, Survival skills
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The industrial air ventilation system with supply fan in underground bomb shelter Stock Photo | Adobe Stock
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