Pirunkirkko Cave, Heinola

Pirunkirkko is an impressive rapakivi granite rock formation in Paistjärvi Hiking Area in Heinola. It is a leaning cliff forming a cave that resembles a gigantic lean-to shelter. The cave formed along a fracture zone at the foot of a cliff consisting of 1 630 – 1 640 million year-old rapakivi granite. The continental ice sheet has transported the loose rock material away, sculptured the cave and made the cliff surface smooth. The cave is 40 metres long and 3–8 meters high. According to folktales, local people used Pirunkirkko as a refuge during hostile invasions in the 18th century.