Priest's Grotto
Priest's Grotto (Ukrainian: Озерна, lit. 'lake') also known as Ozerna or Blue Lakes Cave, is a cave in western Ukraine near the village of Strilkivtsi, Chortkiv Raion, Ternopil Oblast (Province). Priest's Grotto is part of the extensive gypsum giant cave system, and is one of the longest caves in the world with over 140.49 kilometres (87.30 mi) (2017) of explored passages.