Devil's Nest: A Geological Wonder in Hollola

Devil's Nest, known locally as Pirunpesä (literally "Devil's Nest"), is a captivating nature preserve located in Hollola, Finland. This unique attraction is renowned for its striking rock formations and serene natural environment, making it a haven for nature lovers and outdoor adventurers. The canyon is located in the Tiirismaa Nature Reserve, east of the Tiirismaa television and radio mast. The gorge cuts through the quartzite bedrock of Tiirismaa, with vertical walls up to 20 meters high. This impressive natural formation has been a well-known attraction since the 1800s. The Tiirismaa rock area is nationally valuable and one of the most significant sites in Salpausselkä Geopark. The 4.5 km long Tiirismaan kierros hiking route passes through Pirunpesä, featuring a lookout point, hut shelter, and fireplace. Devil's Nest was formed along a weak zone in the Tiirismaa bedrock, where the stone material cracked and broke over time. At the end of the Ice Age, about 12,000 years ago, the southern edge of the continental glacier blocked the ice lake formed by the meltwater of the glacier on the north side of the cliffs of Tiirismaa. The Pirunpesä gorge was created when the water masses of the ice lake erupted through a broken part of the rock to the south, taking loose rock material with it. The gorge has a sort of funnel, where the water from the lake entered the gorge. The finer material was transported further with the current, but the larger boulders piled up to form a boulder deposit at the southern break-through point of the channel. Visitors can explore the area via well-marked paths, admiring the sheer rock walls and surrounding nature. The Tiirismaa area offers a peaceful environment for outdoor activities and hiking.