Prohodna Cave

Worth a detour

The longest cave tunnel in Bulgaria, open at both ends, with two near-identical holes in the roof that drop daylight into the middle of it. Locals call them the Oknata, the windows; the internet calls them the Eyes of God. It costs nothing, takes twenty minutes, works in any weather and sits half a kilometre from Karlukovo. As easy as a cave ever gets.

Story

Background

Prohodna runs east to west through the limestone of the Karlukovo karst, above the Iskar gorge. It is a corridor rather than a cave system — a surviving span of rock bridge, left standing when the passage either side of it came down. The rock is Cretaceous limestone full of shell fragments and ammonites; the Iskar once filled this level and now runs well below it. The vault lifts more than forty metres above the floor. It was made a natural landmark in 1962.

The holes are the reason anyone comes, and they earn it for a reason people usually miss: the two entrances sit at very different heights, so most of the light inside arrives down through the roof rather than in from the ends. That is why the effect works from within, and why it changes completely through the day. The name Eyes of God is recent and imported; the old name is simply the Oknata.

The rest is prehistoric occupation traces, a long list of films — Time of Violence onwards, plus several foreign productions — and the fact that this is one of the very few caves in Bulgaria where people bungee jump through the roof.