📜 Historic medieval canal system in Salzburg, Austria. 🔍 One of Europe's oldest tunnel systems, dating back to the 8th century. # Why Go 🚶 Explore ancient subterranean passageways during annual tours 💡 Witness historical engineering marvel and see water powering mills and city infrastructure 🌊 Enjoy surfing, swimming in cool, clear water during summer, and easy access for walking and cycling along the canal # Why Avoid 🚫 Not wheelchair accessible 🗓️ Underground tours are limited to three weeks in September 🥶 Warm, dirt-resistant clothing, rubber boots, and a flashlight are required for tours # Tips 📍 GPS coordinates lead to the grain mill at St. Peter's Abbey 📞 Book private tours in advance via phone: +43 699 13790310 🚌 Accessible by public transport, bus line 5 to Georg-von-Nissen-Straße # Cost 💰 Adults €10, others €7. Pay guide directly. # Hours 🕒 Tours: First 3 weeks of September, daily 9 AM - 7 PM (booking required) 🏊 Swimming: June to August (not possible in September)