Baradla Cave

Baradla Cave (Baradla-barlang) lies in the Aggtelek Karst in northern Hungary and is the Hungarian side of the Baradla–Domica cave system, which continues under the border into Slovakia. Length figures vary: from just under 24 kilometres (Wikivoyage, of which about 5.6 lie in Slovakia) to more than 25.5 kilometres (Wikipedia); the main passage is about 7 kilometres. The natural entrance is near Aggtelek at the foot of a high white cliff; the entrances at Lake Vörös were built in 1890.

Sights include huge halls (the Giants' Hall is 125 metres long, 55 metres wide and 30 metres high) and a stalagmite 37.2 metres tall. More than 500 animal species live in the cave, including 21 bat species. Baradla and the other caves of the Aggtelek and Slovak Karst have been a UNESCO World Heritage Site since 1995.

There are three entrances: Aggtelek (about 1 kilometre, around 60 minutes), Lake Vörös (the longest lit section, around 100 minutes, ending at Jósvafő) and Jósvafő (about 1.4 kilometres round trip, around 60 minutes). These figures come from Wikivoyage; because they vary, check and book tours and dates beforehand. Getting there: one direct bus a day runs from Budapest-Stadion and takes about 4.5 hours; there is no local public transport or taxi service on site.