8 hours underground in the Ostwall (Festungsfront Oder-Warthe-Bogen) in Poland! We crawl through water wells or trudging knee-deep in water, discover one tank factory after another, climb huge staircases, hide a few Geocaches and even encounter real ammunition of the Nazis from the Second World War. At the end we just explored 1/3 of the 35 km large tunnel system! Fascinating and frightening at the same time about the bunker system of the Nazis established here in WW2. However, I'm glad that it never came into use, but at least we geocachers & Adventurers have fun in our days... :)

Video & News:   / nathusworld  
Pics:   / worldofgeocaching