For 30 years, tourists speeding south through the Sonnenberg tunnel to Italy have had no idea they are driving through one of the world's biggest nuclear bunkers.
Swiss authorities could never be accused of failing to take the threat of nuclear war seriously. But they are now closing down most of this eerie communal shelter as part of a rethink of threats to national security.
"The emergency scenario is much different now from the one during the Cold War," tour guide Julia Meier said.
The big problem with Sonnenberg is that it takes up to two weeks to get ready as a safe haven for 20,000 local residents.
And the doors don't close.
The shutdown is part of a reassessment of Swiss defence priorities, from the relative certainties of the Cold War to the unpredictable threats of terrorism and natural disasters, said Civil Protection Ministry spokesman Pascal Aebischer.
The Swiss Government figures it will now have several years' warning of rising tensions before the outbreak of any major international conflict that might threaten the country.
So in an effort to save public money, the country will maintain only those facilities required to deal with unexpected disasters and emergencies, and which can quickly be made operational.
"These days, damage from catastrophes and emergencies stands at the centre of our calculations," Aebischer said.
Switzerland passed a law at the height of the Cold War in the 1960s requiring space in a nuclear fallout shelter for every resident.
The city of Lucerne, at the foot of the Alps, found it had too little space and decided to solve the problem by using new motorway tunnels on the main tourist route south from Germany to Italy under the Sonnenberg mountain on the edge of town.
A shelter was built in the 1970s connected to the two new tunnels, creating a virtual city within a mountain complete with air filtration, a command centre, a prison and a hospital with space for 350 patients.
Value of shelters questioned
Lucerne's authorities have now decided such a giant facility thought to be the largest in Europe no longer makes sense and will reduce its capacity to the 2,000 people who can fit into the command centre in an effort to save some of the maintenance costs of 500,000 Swiss francs (US$400,000) a year.
"Today in peacetime, the value of the shelters is being questioned," Aebischer said. "Terrorism is also a much greater threat."
While Sonnenberg's central bunker will be maintained, the motorway tunnels, which would have been closed off with giant doors, will no longer be used as shelters.
These days, Switzerland's nuclear bunkers many of which are cellars of houses and apartment blocks may seem as outdated as the contents of Sonnenberg, with its 30-year-old signs and medical equipment.
In the event, the shelter was never used in conflict luckily, since in a practice run in 1987 it took two days to close the tunnel doors because they had not been properly maintained.
Conditions would be far from comfortable. The administration and medical facilities are in a purpose-built bunker with running water and toilets, but civilians would have slept in four-tier canvas bunks in the two motorway tunnels.
Standing in the bunker, it's easy to imagine the fear of 20,000 men, women and children packed into this complex of command rooms, operating theatres and air filtration systems.
The clocks have a panel that shows red in daylight and black at night time, while the light yellow and green colour scheme supposedly designed to ease the mind achieves the exact opposite among some visitors.
Source: China Daily