The Bilstein Cave was discovered in September 1887 during road construction works. Shortly thereafter, the first guided tours of the cave took place. The cave was explored and has been open to visitors since 1888 as one of the large Sauerland caves.
The Bilstein Cave is only a part of the larger Bilstein Cave System. Of the 1,850 meters of the entire cave system, about 400 meters can be comfortably walked. The remaining meters are reserved for well-equipped spelunkers. The deeper cave areas are under water for months, only in dry summers these cave passages are above the water table.
This is one of the special features of the cave: an active cave stream flows through the lower level of the cave system. A new cave is formed under our feet, because the water washes out the cave further and deeper there every day.