Project Riese, Nazi military complex in Owl Mountains, Poland.
Project Riese is a military tunnel system in the Owl Mountains of southwestern Poland, consisting of seven separate underground sites with several kilometers of passageways in total. The tunnels were never completed and today still show traces of blasting work, concrete formwork, and temporary support beams in the rough rock walls.
Construction began in 1943 and continued until the war's end in 1945, when Soviet troops approached and the sites were partially demolished. Around 13,000 prisoners from concentration camps worked here under guard, and many did not survive the conditions.
The name Riese means giant in German, reflecting the enormous scale of the planned facility. Visitors today encounter memorials for the forced laborers who toiled here under inhumane conditions, with their stories told through on-site documentation.
A good flashlight is necessary for most sections, as artificial lighting is sparse. Some tunnels are accessible only with a guide, while others can be explored independently, though sturdy footwear is recommended due to uneven floors and puddles.
The exact function of the complex remains unknown to this day, leading to speculation about underground weapons production or a headquarters for leadership. Some tunnels were flooded after the war, while others partially collapsed, leaving large areas inaccessible even now.
The community of curious travelers
AroundUs brings together thousands of curated places, local tips, and hidden gems, enriched daily by 60,000 contributors worldwide.
