Into the Mountain: Exploring Zeljava’s Underground Airbase
Walk through a Cold War relic carved into Plješevica mountain—two hours of subterranean history and hands-on exploration
You step off the minibus where the asphalt thins and the hill becomes rock. A ragged mouth of concrete yawns into Plješevica mountain, and for a moment the air feels different—cooler, held hostage beneath tons of stone. Your guide's flashlight slices a cone across a vaulted hangar, where echoes answer every footstep twice. This is Zeljava: a Cold War citadel carved into a mountain on the Croatian–Bosnian border, a place where engineering, secrecy, and history meet a hardscrabble kind of beauty.
Trail Wisdom
Bring solid footwear
The tunnels are damp and uneven—sturdy boots with good traction reduce slips and make walking on concrete and rubble comfortable.
Carry a reliable light
Even if guides provide lamps, a personal headlamp or small flashlight with spare batteries helps for photography and tight corners.
Listen to the guide
Guides know unstable areas and safety rules—stay with the group and obey warnings about restricted zones.
Protect your camera gear
Long exposures work best underground—bring a small tripod and lens cloths to handle damp conditions.
Local Knowledge
Hidden Gems
- •Short viewpoint on the Plješevica ridge for panoramic shots of the Bihać valley
- •Small roadside stands near Plitvička Jezera selling trout and local cheeses
Wildlife
Brown Bear, Golden Eagle
Conservation Note
The site is fragile—stick to marked paths, don't remove artifacts, and support licensed guides who help monitor and protect the complex.
Built during the Cold War era, Zeljava was one of Europe's largest underground airbases and was heavily damaged during the conflicts of the early 1990s.
Seasonal Guide
spring
Best for: cooler visits, fewer midges, flowered valleys above ground
Challenges: mud at trailheads, variable weather outside
Spring is pleasant—underground temperatures are stable, while the surrounding hills green up and make a good pairing with a surface hike.
summer
Best for: pairing with Plitvice Lakes, long daylight, easier travel logistics
Challenges: higher tourist numbers at Plitvice, warm above ground temperatures
Summer brings more visitors to the region; the tunnels remain cool, but plan transport and bookings ahead.
fall
Best for: fewer crowds, crisp air outside, rich landscape colors
Challenges: shorter daylight hours, cooler temperatures
Fall is ideal for combining history and landscape photography—the mountain air sharpens, and crowds thin.
winter
Best for: atmospheric light, quiet site visits
Challenges: cold and possible snow on approach roads, limited services in nearby towns
Tours operate year-round, but winter requires warmer layers and careful transportation planning.
Photographer's Notes
What to Bring
Sturdy hiking shoesEssential
Grip and ankle support for wet concrete and rubble inside the complex.
Headlamp or compact flashlightEssential
Supplement operator lighting for navigation and photography in dim tunnels.
Lightweight tripod
Enables long-exposure shots of hangars and control rooms in low light.
Insulating layer and waterproof jacketEssential
Keeps you warm and dry during chilly approaches and wet conditions outside the tunnels.
Common Questions
How long is the tour?
The guided visit is about two hours in duration, which covers the main underground hangars and selected control rooms.
Is the interior safe to enter?
Tours are operated with safety in mind; guides mark unstable areas and provide instructions—follow their directions and stay with the group.
Can I take photos inside?
Yes; photography is allowed, but bring a tripod or steady hand for low-light conditions and be mindful of other visitors.
Are children allowed on the tour?
Policies vary by operator—children are usually permitted if supervised, but check age or mobility restrictions when booking.
Do I need special permits to visit?
No formal permits are typically required for guided tours, though private exploration of restricted areas is discouraged and potentially unsafe.
What are the language options for guides?
Guides often speak English and regional languages; confirm language availability when booking your tour.
What to Pack
Headlamp (for low light), Sturdy boots (wet concrete and rubble), Lightweight tripod (photography), Insulating waterproof layer (cold/wet approaches)
Did You Know
Zeljava was one of the largest underground airbases in Europe and was built inside Plješevica mountain during the Cold War; it was heavily damaged and partly destroyed during the conflict in 1992.
Quick Travel Tips
Book guided tours in advance; Expect patchy cell service near the site; Combine the tour with Plitvice Lakes for a full day; Carry cash for small local vendors
Local Flavor
After the tour, head to Plitvička Jezera village for trout or lamb at a local konoba and try šljivovica (plum brandy) in a cafe; in nearby Bihać you’ll find Bosnian coffee houses and casual eateries serving ćevapi.
Logistics Snapshot
Closest major airport: Zagreb (ZAG) ~2.5–3 hours drive; Driving distance from Plitvička Jezera: ~40–60 minutes depending on route; Cell service: Good in towns, patchy near the site and none deep inside tunnels; Permits: None required for guided tours—book through licensed operators.
Sustainability Note
This historic site is fragile—pack out all trash, avoid touching or removing artifacts, and support licensed guides who help preserve and monitor the area.