What got you interested in urban exploration?

I was in high school at the time. It was summer and all my friends were away on the coast. I was bored and started searching for interesting locations in Zagreb I could visit. During this time I found an incomplete map and some photos of an abandoned Second World War tunnel complex. All the clues pointed to it being at the base of Sljeme mountain — a popular hiking destination. So I decided to make a day of it: I took my bike and went exploring. I found [the tunnels] after a few hours and even managed to get inside.

After that, I kept taking my friends to find and explore other deserted monuments. We started Croatia Infiltration as a blog in 2008 to share our exploits. But as the only urban explorers in Croatia to actively post online, we began attracting attention. Brands started getting in touch to ask if we could help them set up events at different abandoned locations. Companies like HTC and Canon would ask us to arrange press trips for journalists, so that they could show off their latest camera’s low-light sensitivity or the signal they could get on their new mobile phone. We realised we could make a business just by being onsite and knowing everything about a particular place. Now, we also offer professional location services for film crews and photographers who want to shoot these places. We’ll organise everything: permits, logistics, camera equipment, people on set. At one point we worked on a multi-million dollar, four-day shoot for Mazda, with 150 people on location.

We’ve explored tens of different locations, but the most thrilling was probably the Žrnovnica Command Centre (Object – 182). Getting in is a real feat of courage as you need to pass by a field that’s supposedly mined. First, you need to find your way through the thicket, which is like a jungle. Then, you need to climb down a 60m vertical escape tunnel, which is the only way in. The last time we were there — just two weeks ago — it took us almost four hours to find the tunnel, and another two to get everyone inside. It’s a special experience which always takes over 12 hours of work.