crystal palace , Mlynki , crystal cave , in the Ternopil region of Ukraine . 水晶宮 ， mlynki ， 水晶洞穴

photographer Oleg Grigorev 

The Mlynki: Inside one of the most beautiful caves in the world | Mail Online http://www.dailymail.co.uk/news/article-2169580/The-Mlynki-Inside-beautiful-caves-world.html