Psí kostel

Nature, as the architect, created a breathtaking spectacle in the middle of the Hradčany walls. A sandstone cathedral with many windows and entrance portals. The cave formed in a calcareous sandstone deposit by selective dissolution of carbonate. The dissolution first created smaller cavities, which began to interconnect over time to form a larger cave. Perhaps in the Middle Ages, however, these spaces were enlarged by man. The cave has several entrances separated by rock columns. The length of the system of interconnected cave niches exceeds 20 m.

Psí kostel as well as Husovy kostely are a system of natural caves and niches formed in at least 2 m of calcareous sandstone. The fine-grained sandstones of the upper part of the Jizera Formation in the western part of the Hradčany walls contain numerous interbeds of pinkish sandstones with recrystallized calcite as well as vaguely limited, several metres thick limestone sandstone. These sandstones give rise to various forms of selective weathering and karsting. The most famous such formations are Psí kostel (Hundskirche in German) and the Rock Gate nearby.