After World War II, Albania became a Stalinist state under Enver Hoxha, and remained in isolation until its transition to democracy after 1990.
During the 1970s, Hoxha started a bunker project as an effort to protect Albania from what it saw as the risk of foreign aggression.
Forty-seven years of communist rule ended with elections in 1992.
Today, thousands of bunkers have been destroyed to make way for new buildings and roads.
But the government is protecting the ones that survive.
The biggest nuclear bunker is near the capital Tirana, and was re-opened three years ago as a tourist attraction.
TRT World's Iolo ap Dafydd reports.