The Château de la Roche du Roi rises above the southern side of Aix-les-Bains, a romantic landmark from the town's resort age. It is more a sight from the outside than a conventional visitor attraction, but it gives the spa quarter a useful bit of drama.
Use it as part of a walk through the old villas and palace hotels. The pleasure is in seeing how Aix stretched uphill from the baths toward views of the lake and mountains.