The amusingly shaped former Fort Thüngen (18C) was built deep in the woods. It earned its nickname – Three Acorns – because of its acorn-shaped towers. It will eventually house the fort museum, designed by French architect Jean-Michel Wilmotte and dedicated to the genesis of its identity. A long underground gallery (169m) leads to the Fort Obergrünewald below. The surrounding Three-Acorn Park (Dräi Eechelen), a very relaxing landscaped park, was designed by Michel Desvigne and Christine Dalnoky.