Swiss military bunker entrance carved into Alpine rock face

Declassified

360,000 Secrets
Beneath the Alps

The definitive guide to Switzerland’s extraordinary hidden bunker network — from Cold War fortresses carved into mountains to fallout shelters beneath family homes.

360K+
Total Shelters
107%
Population Coverage
1886
First Bunker Built
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Interactive Database

Explore the Network

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Explore all 15 documented sites →

Bunker Profiles

Notable Installations

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Museum
Sonnenberg
Lucerne · Mount Sonnenberg
Built 1976 · Capacity 20,000
Museum
Sasso San Gottardo
Ticino · Gotthard Pass
Built 1943 · Declassified 1998
Repurposed
La Claustra
Gotthard Massif · 100m depth
Boutique hotel · 17 rooms
Active Military
Fort Heldsberg
St. Margrethen · Rhine
Built 1939 · Artillery Fortress

The Dossier

Intelligence Briefings

A monthly dispatch covering newly declassified sites, policy updates, visitor guides, and deep dives into Switzerland’s hidden infrastructure.