Vojenský objekt v Prokopském údolí, Military bunker in Prokopské Valley, Czech Republic

The underground military complex in Prokopské údolí, known as K-116 or VÚ 2508, occupies a former limestone quarry and an unfinished Nazi underground factory. Three parallel tunnels about 300 metres long and up to 8 metres high were dug here, and a small underground station with a transshipment point was built. One entrance lies in the quarry near the former Dalejský mlýn in Jinonice.

The site began as a limestone quarry in the 19th century, and the large Prokop Cave was gradually quarried away. During World War II the Nazis partly converted it into an underground Junkers plant, code-named Kali, for aircraft parts; three parallel tunnels about 300 metres long were dug, but the factory never became operational. After the war the tunnels held vegetable stores, and from the late 1960s the army took over the site.

The name Prokopské údolí comes from Saint Prokop, to whom a church stood on the limestone cliff above the cave entrance. Adam Schwarzenberg had it built in 1711–1712; it was demolished in 1966. The army later leased a small spot on Prokopská skála for a visible cross commemorating the saint.

The quarry and the adjoining rocky hills are fenced off as a guarded military area, so the tunnels and entrances cannot be visited. The army has rented a small spot on Prokopská skála for a visible cross commemorating Saint Procopius. Views of the valley are possible from the surrounding public paths.

The army leased a small spot on Prokopská skála for a visible cross commemorating Saint Procopius, even though the church itself was blown up in 1966. The site is still guarded, and foreign geologists photographing the rock were reportedly detained by the military police.