Embedded deep inside a remote Bosnian mountain, a vast, top-secret bunker built to shield a communist dictator from nuclear attack has been converted into an art gallery.

For its first exhibition, Military Installation D-0 -- as the hideout for Josip Broz Tito is officially called -- is hosting a contemporary show called "Time Machine".

Emphasising the bunker's past, organisers said by filling the Cold War relic with modern-day art, visitors would be inspired to "time travel" simultaneously into the past, present and future.

"It can be a curiosity, an attraction that people will come to see," said Branislav Dimitrijevic, curator of the show featuring contemporary artists from across Yugoslavia and Europe.

Marshal Tito ruled the former Yugoslavia from the end of World War II until his death in 1980. Although a professed communist, he resisted domination by the Soviet Union.

Heading a non-aligned nation through the height of the Cold War, Tito was perpetually afraid of foreign invasion. He riddled his country with underground bunkers where he could seek refuge if a conquering enemy, or nuclear warhead, approached.

Three white houses above ground on the slopes of the southern Bjelasnica mountain in Bosnia-Hercegovina are the only signs that give away Military Installation D-0, the sophisticated anti-nuclear facility that unfolds below.

The former Yugoslav army JNA spent 26 years and 4.5 billion dollars (3.2 billion euros) building the complex, some eight kilometres from Konjic and 50 kilometers (30 miles) from Sarajevo.

Finished in 1979, the 6,500 square-meter (69,940 square feet) bunker -- complete with a hospital, decontamination room, command and control centre, and space for Tito, his wife and some 350 leaders of his regime -- had never been seen by the public.

All that has now changed.

"Our idea was to make this place a space for art and culture," said curator Dimitrijevic. "We wanted to transform the bunker into a museum of artistic inventions, with artists leaving their works in this place, works that will communicate with the space."

So far, some 5,000 people have visited the exhibition that runs until September 27. Visitors can also take guided tours of the facility three days a week, three times a day.

-- Even my wife didn't know my job --

Retired Bosnian Colonel Serif Grabovica, for one, is glad the "top secret" days are over. With a handful of trusted officers and maintenance men, he ran the site from 1979 until the Bosnian war broke out in 1992.

"For 13 years I did not tell anyone what my job was. Even my wife did not know about it," the 63-year-old retired Bosnian officer told AFP.

"There were 15 of us ... We signed an obligation to keep a state secret," he explained.

The bunker's current commander Almir Gakic said this potential art haven was almost destroyed.

At the outbreak of the Bosnian war, he said, the withdrawing Yugoslav soldiers ordered him to set off explosives at each of the three entrances, to collapse the underground complex.

"But I cut the wires before leaving the space," he recalled.

Gakic was equally proud that the modestly decorated, horse-shoe shaped bunker is still "functioning perfectly".

Its temperature is maintained at 21 and 23 degrees C (69.8 and 73.4 degrees F) and humidity at 60 and 70 percent, what Gakic called ideal conditions in which to work and live.

Two large German-made 550 KW generators are still programmed to kick in 18 seconds after a power failure.

Gakic said his main regret is that Tito never actually visited the then state-of-art facility, although his portraits are still on some of the walls.

The irony of Military Installation D-0, said curator Dimitrijevic, is that while Tito spent lavishly on safeguards against a nuclear attack, his Yugoslavia was ultimately destroyed by "an extremely bloody conventional conflict."

Bosnia's 1992-1995 war between its Croats, Muslims and Serbs claimed some 100,000 lives.