Devil's Throat Cave
The 72nd longest cave in the world
Devil's Throat Cave, or Dyavolsko Garlo ([ˈdʲavoɫskoto ˈɡɤrɫo]), is located in the western Rhodopes close to the village of Gyovren in Bulgaria, near its border with Greece. A popular tourist attraction, Devil's Throat branches from Trigrad Gorge. The cave’s entrance resembles a devil’s head, and down its throat rushes a massive waterfall that from ancient times has given birth to numerous legends. It is a fact that nothing carried by the river into The Devil’s Throat Cave emerges back from it. Many attempts have been made to track pieces of wood and other material through the cave, but they all vanish without a trace in the underground river. Experiments performed with dyes have shown that it takes more than an hour and a half for the water to traverse the short distance from one opening to the next, fueling speculations about an extensive system of underground streams in the cave.
Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).