Carved deep into Mount Plješevica on the border of Croatia and Bosnia and Herzegovina, Željava was once one of the largest and most secret military air bases in Europe. Built during the Cold War, it was engineered to withstand a nuclear strike and remained a closely guarded Yugoslav military secret for decades.
Today, Željava stands as a powerful historical attraction. Vast underground tunnels, runways fading into the forest, and the raw atmosphere of a bygone era draw history enthusiasts, urban explorers, and curious travellers from around the world. A visit to Željava is more than a walk through ruins—it is a journey into a time when this mountain concealed the strategic heart of the region’s air defence.