Ostrężnicka Cave

In the woods beside the road from Żarki to Janów stands a limestone crag that cavers compare to a block of Swiss cheese. Ostrężnicka Cave runs right through it, with a network of passages about 90–98 m long and six openings, while traces of a medieval watchtower survive on top of the same rock. It is one of the most accessible caves in the northern Polish Jura – a short walk, an impressive portal and plenty to explore with a torch.

The rock, the cave and the watchtower

The cave formed in Upper Jurassic limestone as underground water widened cracks in the rock. The shape of the passages and the potholes visible in the ceiling show that large volumes of water once flowed through under pressure – the cave is part of an old resurgence that drained the slopes of the Wiercica valley. The main opening, at the north-eastern foot of the rock, is a smoothly scoured portal about 5 m high and 3 m wide. Two smaller openings face north-west, and three more lie in the south wall, about 5 m above the main entrance.

In the Middle Ages a small castle stood on top of the rock, traditionally linked with Duke Władysław of Opole. The cave chambers probably served as its cellars and storerooms. Today only fragments of its walls remain.

Inside the cave

From the portal a short passage splits into two wider ones, about 3 m high. The left one climbs gently to an opening in the south wall; the right one leads to a small chamber with potholes in the ceiling. Further in, the ceiling drops and in places you have to crawl on your knees. There are hardly any dripstones – the appeal lies in the water-sculpted rock. The temperature inside is about +6°C, falling below zero in winter. There is no lighting.

Did you know?

• The cave was first described by Kazimierz Świerzyński in 1848; for a long time only individual chambers were known, as the connecting passages had not been found.
• Treasure hunters have dug here many times. Local legends tell of hidden riches, a shepherd trapped underground and robbers buried alive.
• The same rock and its surroundings hold several smaller rock shelters and fissures, including the Larger and Smaller Shelters of Ostrężnik.

Tripto tip

The cave lies in the Ostrężnik nature reserve, in the village of Siedlec (Janów municipality). The slaskie.travel portal says that access should be arranged with the Regional Directorate for Environmental Protection in Katowice – check the current rules before you go. Park at the Ostrężnik bar car park on provincial road 793 and follow the blue trail for about 10 minutes. Bring a head torch, shoes with good grip and a warm layer even in summer. An hour is enough for the cave and the watchtower ruins; nearby, don't miss Twardowski's Gate and the springs of the Wiercica in Złoty Potok.