Route 46 is an almost 70 km long unfinished section of motorway in Germany that runs parallel to today's A 7 between Fulda and Würzburg.
Construction of this planned Reichsautobahn began in 1937 and was stopped in 1939. A total of around 30 km of continuous route was built. The withdrawal of workers and materials for war purposes and the introduction of new standards after construction began made work more difficult. After the end of the Second World War, the plan was abandoned. Instead, a route was chosen that runs past Schweinfurt and has larger curve radii. According to documents from local motorway maintenance departments, this was also due to the changed political geography: due to the inner-German border, the eastern West German areas of the Rhön and the Spessart had become relatively poorly accessible border areas without the hinterland connection (to Meiningen, Bad Salzungen, Eisenach). In addition, a connection with route 85, which had begun in Thuringia, was now obsolete.
Numerous fragments of the almost completed motorway are still in the landscape, such as sections of the route, bridges and bridge pillars. They have been listed as historical monuments since 2003. There are almost a dozen unfinished structures on the old route, most of them in the forest. In Rupboden, a county road passes under the tree-covered route, which is still clearly visible from above. In the Schulruh district between Burgsinn and Gräfendorf, a large bridge structure without filled foundation slopes spans the MSP17 (cross connection Sinntal-Fränkisches Saaletal) at a ridge height of 395 m above sea level. In Gräfendorf, the larger of two unfinished pillars of the planned Saale overpass serves as a climbing rock for alpinists (180 m above sea level).
Source: Wikipedia