Inside the secret Soviet bunker built to withstand a 20-kiloton nuclear blast: The abandoned Cold War airbase that housed a fleet of fighter jets opens to the public

A sprawling Cold War-era Soviet bunker built to withstand a 20-kiloton nuclear blast but left abandoned for decades is being transformed into Europe’s newest tourist attraction.

The underground Zeljava Air Base, carved into a mountainside on the border between Croatia and Bosnia-Herzegovina, was once one of the continent’s largest military complexes.

But after it was abandoned during the Serbo-Croatian War in 1992, it lay dormant for decades, with only the occasional intrepid adventurer venturing into its crumbling cavernous core.

Plans are now in the works to open the sprawling complex, just a stone’s throw from southern Europe’s busiest national park, Plitvice Lakes, to tourists – as shocking new images of the sprawling base have been revealed.

It was secretly built in the 1960s for $6 billion 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 – and has about its own power, water and water. Cleaning and ventilation systems and can work autonomously.

The sprawling Cold War-era Soviet bunker was built to withstand a 20-kiloton nuclear blast but remained abandoned for decades

Abandoned during the Serbo-Croatian War in 1992, it remained silent, with only the odd intrepid adventurer venturing into its crumbling cavernous core (pictured is Mario Garbin, with a flashlight) the dank depths of the bunker to explore.

Now there are plans to open the huge complex, just a stone’s throw from southern Europe’s busiest national park, the Plitvice Lakes, to tourists (visitors Angelo Virag (R) and Mario Garbin (L) photograph Zeljava’s dark tunnels ). )

At its height, the bunker had five runways and could accommodate nearly 60 MiG-21 aircraft, while the approximately 3.5 kilometers of tunnels also housed command centers, offices and dormitories for 1,000 Soviet soldiers.

The remains of the giant 100 ton retractable concrete doors at the four entrances are still visible and the metal supports jut out from the structures.

“All systems were state-of-the-art at the time,” said Mirsad Fazlic, a former pilot who worked at the base for nearly a decade in the 1980s.

“It was the best military and civilian technology at the time.”

During the wars following the fall of communism and the breakup of Yugoslavia in the 1990s, the facility was destroyed by the remnants of the Yugoslav army using high explosives.

“Everything that was there, all the equipment, everything was burnt,” Mr. Fazlic said. “Only the tunnels and walls remained.”

After its destruction, the base lay largely empty and in disrepair, attracting adventurous tourists eager to explore the rusted ruins of the bunker’s maze of tunnels and derelict aircraft.

That changed in 2016 with the release of a Slovenian mockumentary called “Houston, we have a problem!” with the base.

This photo taken on October 4, 2023 shows a US Army Douglas C-47B Dakota aircraft covered in decals at the underground Zeljava Army Airfield in the heart of the Pljesevica Mountains on Croatia’s border with Bosnia

On October 4, 2023, visitors explore some of Zeljava’s 3.5 kilometer long tunnels in the heart of the Pljesevica Mountains

Much of the hidden depths of the former Soviet bunker complex have rusted away after decades of neglect

Visitor Mario Garbin looks at large fuel tanks on the Zeljava. The underground base is designed to withstand a nuclear blast

According to local residents, the state complex has since attracted more than 150,000 people a year.

Authorities in the region hope that if properly marketed, the base could attract many more tourists, especially some of the 1.7 million tourists who visit the nearby Plitvice Lakes National Park each year.

“By revitalizing Zeljava, we will create additional content for the national park and allow tourists to stay longer,” said Ante Kovac, the region’s mayor.

The base has hosted auto races, and officials believe its extraordinary size could house data centers, host parties or create a Cold War museum.

Today, visitors walk with flashlights through the damp, pitch-black tunnels, carefully avoiding holes in the ground, while some drive through parts of the base.

“It’s crazy that time is frozen,” said Angelo Virag, a photographer from the Croatian capital, Zagreb, who was impressed by the “absolute genius of the technology”.

Locals estimate that the state-owned company attracts more than 150,000 people each 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 looks at the ventilation system in the large underground former Soviet military base

Authorities in the region hope that if properly marketed, the base could attract many more tourists, especially some of the 1.7 million tourists who visit the nearby Plitvice Lakes National Park each year.

Car races have already been held on the bass. Pictured is one of the five large runways once used by the base

His cousin Mario Garbin of Perth, Australia, raved about the “raw, authentic nature of the infrastructure that has remained untouched for thirty years.”

Aviation fanatic Hamdija Mesic from the nearby Bosnian town of Bihac said he hoped the two outliers in Bosnia would soon be reopened to other pilots.

“Such a large facility, abandoned by the ravages of time, exists nowhere else in the world,” he told AFP.

However, others hoped that the site would remain as it is.

“There are no signs saying where to go and what to see, it’s more a place of discovery,” Maria Moreno, a 33-year-old interior designer from Spain, told AFP. “That’s why I liked it.”

“If you turned it into a tourist attraction, it would lose its charm.”