In the northern part of the Palatinate Forest, east of Kaiserslautern, there is an extraordinary number of burial mounds from prehistoric times. Over 300 burial sites are known and probably form the largest contiguous deposit in Germany. The area lies in the center of the former Celtic settlement area, within sight of the Donnersberg, which was the site of one of the largest Celtic towns over 2,000 years ago. In addition to these burial sites, there are numerous other traces and signs left behind by the people of past times. Many of these have not yet been scientifically researched and often lie inconspicuously hidden in the forests. Some will perhaps remain mysterious forever. In a joint project between the participating communities of Hochspeyer, Fischbach, Enkenbach-Alsenborn, and Mehlingen, a network of hiking trails totaling 60 km was created in 2008. This network connects over 50 stations, often representing "mysterious signs of time."