The cave was used for illegal production of aircraft parts by the German army during the final phase of World War II.
In the 1960s, a reinforced concrete atomic bunker was built directly inside the natural cave halls.
The military facility, codenamed 'K-5', was designed to withstand a direct nuclear strike.
Human remains and extinct Pleistocene fauna, including cave bears and lions, were excavated here in the 19th century by Jindřich Wankel.
The cave is unique in the Moravian Karst because it lacks extensive dripstone decoration due to historical mining and industrial activities.
Výpustek is a unique cave system in the Moravian Karst near Křtiny, distinguished by its complex history as both a natural wonder and a strategic military facility. Originally explored in the 17th century, the cave served as an underground factory for aircraft engine components during World War II. In the Cold War, the site was converted into a hardened, top-secret nuclear fallout shelter for the Czechoslovak People's Army command. Visitors can explore the preserved bunker infrastructure alongside geological formations. The cave system spans hundreds of meters of passages and large underground halls. The site is part of the Cave Administration of the Czech Republic and maintains a temperature of approximately 8 degrees Celsius year-round. It is located in the Křtinské údolí valley within the protected landscape area of the Moravian Karst.
The entrance to the massive reinforced concrete bunker located inside the main cave chamber.
Wear a warm jacket and sturdy, non-slip shoes, as the cave maintains a constant low temperature and damp floor.
Check the official website for guided tour booking, as access to specific military sectors is limited.
Combine your visit with a trip to the nearby Křtiny pilgrimage church designed by Jan Blažej Santini-Aichel.
Do not attempt to access the site without a booked tour, as the cave entrance is secured and monitored.
Closed on Mondays during the off-season; full operation typically runs from spring through autumn.
Touching cave walls and formations is strictly prohibited to protect the microclimate.
