This route starts from an ibis hotel and goes to the WW2 U-Boat pens, just 10 minutes away, more about the pens later. The route crosses the huge salt production 'fields' of Guerande and uses no fewer than 15 bridges and 1 tunnel as it follows the coast to Concarneau. The 'Ville Close' (as it is called) is the old stone fortified town that has just a few narrow streets filled with shops and restaurants. The ramparts offer spectacular views over the area. We had a taxi from our hotel to visit in the evening. Our hotel was an Ibis budget, a link for this can be seen below.

This route, like many of my routes, is relaxing and scenic as it avoids most of the major roads. The roads are not busy (we went in July) and the ever changing scenery is a joy to travel through. Grab a coffee and a filled baguette just after leaving the submarine base, I highly recommend this as they were really good. The route travels through the strange salt production 'fields' of Guerande where the method for producing salt hasn't changed since the 9th century.

The U-Boat pens at Saint Nazaire:
The strategic location of Saint-Nazaire led the Germans to build a huge submarine base there during World War 2. The construction of this base began at the beginning of 1941.
It contained 14 cells: 8 for repairs and 6 larger cells in which the U-Boats could remain afloat. It housed two U-Boat fleets. It spread over a total surface area of 4 hectares and its concrete ceiling was up to 9 metres thick.

In 1942 a British commando raid attempted to destroy the base. The civilian population suffered greatly from this Allied policy and 80% of the town was destroyed. More can be read about 'The Greatest Raid Of All' in the link below.

The salt marshes of the Guérande and Mès basins are artificially dammed marshes fashioned by man over the centuries. The salt marshes stretch out before you, a breath taking immense mosaic of colours. These 2 000 hectares of salt marshes bear the quality label of ‘Site remarquable du Goût’ (a site of culinary interest and excellence) and are supplied with seawater via the inlets of ‘Les traicts du Croisic and Mesquer’.
Salt workers are the guardians of a unique natural heritage (in French, they're called paludiers, from the Latin word "palus" for marsh). The salt harvest takes place in the summer, but salt workers take care of the marshes throughout the year. In spring, they empty the salt pans where rainwater has accumulated and remove the mud and algae. In autumn, salt must be protected from high tides and from future frosts, while winter is for maintenance of the bottom of the basins.
After seeing how it is produced, you can buy some at the side of the road to take home with you.

As you continue north and cross into Brittany you'll go over the Arzal Dam. This was constructed on the Vilaine river between 1965 - 1970 to protect the town of Redon from flooding. It is one of the few estuarine dams in the world and it includes a fish ladder for migratory fish.
The route travels around the south of the city of Vannes first passing the Noyalo reservoir that supplies drinking water for the city and then an historic tide mill dating back to the 16th centaury.
I have suggested a lunch stop in the medieval city of Auray at the port of Saint-Goustan. There are several restaurants to choose from. Nestled at the bottom of an estuary, Saint-Goustan takes you back in time with its cobbled streets, stone bridge, half-timbered houses and bustling quays.

After lunch there is a succession of 8 bridges to cross as you make your way to Concarneau, a small town in western Brittany famed for its beautiful old town located on a small island called the Ville close. There are lots of fun things to do in Concarneau from exploring its ancient, cobbled streets to sipping coffee in one of the many streetside cafes. Ville close is packed with old stone buildings, many of which have been turned into shops and cafes, where you can grab a coffee, a crêpe (Brittany’s classic snack) and just get lost in the winding alleyways. There are lots of historic landmarks to discover from the old clock tower to the belfry, the Governor's tower, Moor tower, Dog tower, and Horseshoe tower to name a few.

The hotel that I suggest is another ibis that is just short distance away. We booked in and took a taxi back to explore Ville close and all that it has to offer.
Enjoy.