A sprawling Soviet Cold War bunker built to withstand a 20-kilotonne nuclear blast but abandoned for decades is to be transformed into Europe’s newest tourist attraction.
Carved into the side of a mountain on the border of Croatia and Bosnia-Herzegovina, Zeljava Underground Airbase was once one of the continent’s largest military complexes.
But for decades it sat idle, after being abandoned in the Serbo-Croatian War in 1992, with only the occasional intrepid adventurer ever daring to venture into its crumbling cavernous core.
Now, plans are afoot to open the huge complex, which is nestled just a stone’s throw from southern Europe’s busiest national park, Europe Plitvice Lakes, to tourists – as haunting new images of the vast base were revealed.
Built in secret at a cost of $6billion in the 1960s to hide a fleet of Soviet fighter jets in what was then Yugoslavia – a socialist federation that sought a middle ground between Moscow and Washington during the Cold War – it had its own power, water purification and ventilation systems and could operate autonomously.
Carved into the side of a mountain on the on the border of Croatia and Bosnia-Herzegovina, Zeljava Underground Airbase was once one of Europe’s largest military complexes (visitors are pictured exploring the base)
The sprawling Soviet Cold War bunker was built to withstand a 20-kilotonne nuclear blast but abandoned for decades
It sat idle, after being abandoned in the Serbo-Croatian War in 1992, with only the occasional intrepid adventurer ever daring to venture into its crumbling cavernous core (pictured is Mario Garbin exploring the bunker’s dank depths with a torch)
Now, plans are afoot to open the huge complex, which is nestled just a stone’s throw from southern Europe’s busiest national park, Europe Plitvice Lakes, to tourists (visitors Angelo Virag (R) and Mario Garbin (L) take pictures Zeljava’s dark tunnels)
In its heyday, the bunker had five runways and could hold nearly 60 MiG-21 aircraft, with its 2.2 miles or so of tunnels also home to command centres, offices and dormitories for 1,000 Soviet troops.
The remains of the enormous 100-tonne retractable concrete doors at its four entrances are still visible with metal reinforcements protruding from the structures.
‘All the systems were state-of-the-art at that time,’ said Mirsad Fazlic, a former pilot who worked at the base for nearly a decade in the 1980s.
‘It was the then best military and civilian technology.’
During the wars that followed the fall of Communism and breakup of Yugoslavia in 1990s, the facility was destroyed by the remnants of the Yugoslav army, using powerful explosives.
‘All that was inside, all that equipment, everything was burned,’ said Mr Fazlic. ‘Only the tunnels and the walls remained.’
After its destruction, the base sat largely vacant and in disrepair, attracting adventure tourists looking to explore the rusting ruins of the bunker’s maze of tunnels and abandoned planes.
That all changed in 2016 with the release of a Slovenian mockumentary called ‘Houston, We Have a Problem!’ featuring the base.
This picture taken on October 4, 2023 shows Douglas C-47 B Dakota American army airplane covered with stickers at the Zeljava underground army airbase in the heart of the Pljesevica mountain, on Croatia’s border with Bosnia
Visitors explore some of Zeljava’s 2.2 miles of tunnels in the heart of the Pljesevica mountain on October 4, 2023
Much of the hidden depths of the former Soviet bunker complex have rusted after decades of neglect
Visitor Mario Garbin looks at huge fuel tanks at the Zeljava. The underground base was designed to withstand a nuclear blast
Since then, locals estimate the state-owned complex has been drawing more than 150,000 people a year.
Authorities in the area have high hopes that with the right marketing, the base could attract many more, notably some of the 1.7 million tourists that visit the nearby Plitvice Lakes national park every year.
‘By revitalising Zeljava, we would create additional content for the national park enabling tourists to stay a day longer,’ said Ante Kovac, the mayor of the area.
Car races have already been staged at the base, and officials believe its extraordinary size means it could house data centres, or host parties or a Cold War museum.
At the moment, visitors walk with flashlights through its humid, pitch-black tunnels, carefully avoiding holes in the ground, while some drive through portions of the base.
‘It’s crazy that it has been frozen in time,’ said Angelo Virag, a photographer visiting from the Croatian capital Zagreb, who was in awe of the ‘absolute ingenuity of engineering’.
Locals estimate the state-owned complex has been drawing more than 150,000 people a year
Mirsad Fazlic (pictured), a former pilot who worked at the base for nearly a decade in the 1980s, visited the site on October 4
A visitor watches at ventilation plant inside the sprawling underground ex-Soviet military base
Authorities in the area have high hopes that with the right marketing, the base could attract many more, notably some of the 1.7 million tourists that visit the nearby Plitvice Lakes national park every year
Car races have already been staged at the bass. Pictured is one of the five large runways once used by the base
His cousin Mario Garbin, from Perth, Australia, gushed over the ‘raw, authentic nature of the infrastructure that has been left untouched for the last 30 years.’
Aviation fanatic Hamdija Mesic from the nearby Bosnian town of Bihac said he hopes that the two runaways located in Bosnia would be reopened to fellow pilots soon.
‘Such a huge facility abandoned to the ravages of time cannot be found anywhere else in the world,’ he told AFP.
However, others hoped the site would remain as it is.
‘You don’t have signs where you have to go and what to see, it’s more like a discovery place,’ Maria Moreno, a 33-year-old interior designer from Spain, told AFP. ‘This is why I liked it.
‘Turning it into a tourist attraction would lose its charm.’