Háromkürtő-zsomboly is one of Hungary's strictly protected caves, hidden beneath farmland on the Tés Plateau in the Bakony Mountains. This is not a casual walk-in cave - it's a genuine vertical pothole reachable only by experienced cavers equipped with rope-climbing gear.

Formed in Upper Triassic Dachstein limestone along tectonic fissures, the cave splits into two distinct sections. The upper part, down to about 20 metres, is a maze-like network with smooth, water-dissolved walls shaped when it functioned as a sinkhole. Below that, the lower section consists mainly of vertical shafts marked by the corrosive traces of trickling water. Its deepest chamber, the Záporos-terem, holds translucent white flowstone, manganese crusts and pea-like mineral formations. The cave periodically fills with water through seasonal sinkholes - at one point in its history, a nearly 100-metre column of water backed up inside it.

• Village of Tés, about 1.5 km from the centre, in open farmland - easy approach on foot, but entry into the cave itself demands rope techniques and is secured by a locked iron grate

• Strictly protected cave - entry only with permission from the Balaton Uplands National Park Directorate
• Rope-climbing (SRT) equipment is mandatory, along with fixed iron ladders in the entrance shaft
• Not developed for tourism - no lighting or visitor infrastructure

Palaeontological digs in the cave's sediment uncovered 29 species of snails along with wolf bones, making it a valuable scientific site documenting climate and fauna change from the Pleistocene through the Holocene.