You can reach the Marienglashöhle show mine in Friedrichroda conveniently by the Thuringian Forest Line. The natural monument was used for gypsum mining for over 200 years and has one of Europe’s most beautiful and largest gypsum crystal caves with up to 90 centimetre long crystals. They were used, among other things, for decorative stones in pictures of the Virgin Mary, hence the cave’s name. The mine’s entrance tunnels and crystal grotto can be visited all year round, concerts also take place in this unique atmosphere underground.