Source: BBC

By BBC’s Travel Show

Natural caves exist throughout Hungary, but a cave system in the small town of Tapolca has an especially memorable method of exploration. The around 3000-meter-long lake cave system is situated in the heart of the Veszprém county town. It was opened to the public in 1912 after ten years of its discovery and is a popular tourist attraction since then. Small boats can be hired to explore the cave system. As it is 15 -20 meters below the ground the temperature is quite favourable.

Video here