The ruin occupies a space called Pl. St. Pierre. It is right before the Tour Solidor. We could find no information about it on the grounds. We assume it was called St. Pierre and the city was called Aleth at the time. It is mentioned and pictured in a book we own on ancient sites in Northwest France but no details are given. It is what achitecture books call a "double-ender", that is a basilica with apses at each end. This went out of style in the Carolingian period, so may be the ruin is from about 900 AD (a speculation on our part). Our grandson thought it was a cool sight.
The Solidor Tower was erected on a Roman base in 1382. It has 3 contiguous towers each 3 stories high and now contains a modelship museum. Looking north beyond the tower one can see the hydroelectric facility (barely visible in picture#2)
Aleth (St.-Servan) was built on a promontory and once had Roman fortifications (fragments of which may survive). Many people walk around the area to see views in every direction : the Usine, the Rance, St.-Malo, Dinard and visit the ship model Museum in the Tour Solidor. With more time they continue into the Corbieres Park and picnic there (See Tips by others). We did not stay long enough to do either of these as we had not the time.
Inside this super market is hardware, glasses and food shopping. When I come over from Jersey with my car I stock up on food and hardware as it's almost half price compared with at home?!
What to buy: Most food items
A rather pleasant coastal walk through this wooded park and you will be surprised by the magnificent views of the river Rance.