ZELJAVA (AFP) – Like something out of a Bond film, the giant Zeljava airbase was carved into a mountain between Bosnia and Croatia and designed to withstand a nuclear strike.
But for decades it sat idle, with only the occasional intrepid tourist daring to venture into its crumbling cavernous core.
Built in secret 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.
In its heyday, the underground base could hold nearly 60 MiG-21 aircraft, with its 3.5 kilometres or so of tunnels also home to command centres, offices and dormitories.
The remains of the enormous 100-tonne retractable concrete doors at its four entrances are still visible with metal reinforcements protruding from the structures.
Beyond its cavernous interior, the base had five runaways that straddle the border between Croatia and Bosnia.
“All the systems were state-of-the-art at that time,” said Mirsad Fazlic, a former pilot who worked at the base in the 1980s. “It was the then best military and civilian technology.”
During the wars that followed the breakup of Yugoslavia in 1990s, the facility was destroyed.
“All that was inside, all that equipment, everything was burned,” said Fazlic.
After its destruction, the base sat largely vacant and in disrepair, attracting adventurous tourists looking to explore old relics from the communist era.
That all changed in 2016 with the release of a mockumentary called Houston, We Have a Problem! featuring the base. Since then, locals estimate that 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.