Duhlata

Worth a detour

Roughly eighteen kilometres of surveyed passage on seven levels, with six underground rivers running through it, beneath the southern foot of Vitosha at Bosnek. It has been a protected natural monument since 1962 and it is not a show cave. This entry exists so you know what is under your feet on that side of the mountain, not so that you plan a visit to it.

Story

Background

Duhlata lies in the Bosnek karst, the limestone belt on the Struma side of the massif. Surveys differ — the park directorate publishes about 17.5 kilometres, other registers 18.2 — which is enough to put it either first or second on the list of Bulgaria's longest caves depending on whose figures you take. The name comes from the sound of air moving at the entrance.

What makes it scientifically valuable is the life in it. Twenty-two animal species have been recorded inside, six of them bats, and the wider Bosnek karst holds one of the richest underground invertebrate faunas in the country — a couple of crustacean species are known to science from these caves and nowhere else. Cave organisms of that kind tolerate almost no disturbance, which is precisely why the door stays shut.

If you want something in the same landscape that you can actually reach, the Zhivata Voda spring at Bosnek is in the same karst system and is a short walk from the village, and the southern approaches to Vitosha from Bosnek and Chuypetlovo are among the quietest on the mountain. Stand at the entrance if you find it, feel the draught, and leave it at that.