📜 Disused underground oil depot in the Scottish Highlands, built during WWII. 🔍 Holds the world record for the longest reverberation in a man-made structure (112 seconds). # Why Go 🔊 Experience the unique acoustics and echo. 🗺️ Explore a historic WWII bomb-proof fuel storage facility. 🚶‍♀️ Opportunity to visit on a private tour and discover a hidden underground complex. # Why Avoid 🚫 Public access limited to private/occasional guided tours. # Tips 📞 Inquire about private tours for access with local heritage groups.