Dutý kámen, Natural monument in Drnovec, Czech Republic

Dutý kámen is a 600-metre-long sandstone ridge that rises 30 metres above the Cvikov pond near Drnovec, in the Cvikov Highlands. Heat from volcanic magma created five- and six-sided sandstone columns two to three metres high, called the Fan or the Organ. A staircase of 38 steps cut in 1913–1914 leads to the Široký kámen summit.

The site was officially recognized and protected as a natural monument in 1963. This designation was based on its geological importance and role in protecting rare plant communities found in the region.

The name Hohlstein, or Dutý kámen, comes from a cave at the foot of the lookout rocks, popularly also called Zvon (Bell), Soví hlava (Owl's Head) or Rytíř (Knight). The sandstone pillars quarried here since the 19th century were used to decorate ornamental gardens and many Trinity and plague columns in the surrounding area.

The site is best accessed via established paths that are easy to reach from the nearby roads. Visitors should wear appropriate footwear for uneven terrain and stay on marked paths to help protect the area.

The rock formation supports a specialized plant community adapted to the harsh, dry conditions on the stone surfaces. These rare species can only be found in a few locations across the region.