We took a side trip to ride on the Marne Au Rhin Canal and see the amazing Arzviller Incline Lock. This amazing engineering feat that lifts an entire section of canal with sometimes 3 or more boats up 45 meters was constructed in 1964-1968. The Marne Au Rhin connects Paris to Alsace Lorraine, the Rhine, and Germany. The 313 km (194 mi) long canal was the longest in France when it opened in 1853. There's an 85 km bike trail along the canal but we only had time to ride a small part of it. The Vosge Summit near Arzviller is in an incredibly steep part of the canal and prior to 1968 in one short section boats required 17 deep locks in a very short distance. Each lock required a lockmaster with a fairly large house and of course massive amounts of water to operate. The Incline Lock replaced this dramatic section in 1968 so the "Ghost Canal" is now closed off, dry and open only to cyclists. So now the constant stream of boats (mostly recreational) crossing the summit require two long tunnels and the Incline Lock. Many of the disused lock houses are being renovated. There are lots of rental boats along all the French canals... we often wonder if we would enjoy this travel mode (carrying bikes of course) or if the slow pace with so many locks would be too boring.