Marmurova Pechera
Marble Caves (́, Crimean Tatar: Mermer qobası) is a cave in Crimea, at the lower plateau of Chatyr-Dag, a mountainous massif. It is a popular tourist attraction and one of the most visited caves in Europe. Due to its uniqueness, Marble Cave became famous worldwide. Speleologists consider it among the top five most beautiful caves of the planet, and one of the Seven Natural Wonders of Ukraine. In 1992, it was included in the International Association of Equipped Caves.
Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).