Optymistychna Cave
| Optymistychna | |
|---|---|
| Location | near Ukrainian village of Korolivka, Chortkiv Raion, Ternopil Oblast | 
| Coordinates | 48°44′33″N 25°59′37″E / 48.74250°N 25.99361°E | 
| Length | 230 km (140 mi) | 
| Discovery | 1966 | 
| Geology | gypsum | 
| Website | optymistychna | 
The Optymistychna (Ukrainian: Оптимістична, lit. 'optimistic', also known as Peshchera Optimistitscheskaya) is a gypsum cave located near the Ukrainian village of Korolivka, Chortkiv Raion, Ternopil Oblast. Approximately 264 km (164 mi) of passageways have been mapped within. As a result, it is the longest cave in Europe and the seventh-longest cave in the world, after Mammoth Cave, Sistema Sac Actun, Jewel Cave, Shuanghedong and Sistema Ox Bel Ha. It is also the longest gypsum cave in the world.