All is not as it seems inside Chambéry's 15th-century Franciscan cathedral, decorated with 6000 sq metres of trompe l’œil painting. The largest such feature in any building in Europe, the decorations – created by 19th-century artists Sevesi and Vicario – deceive the eyes into seeing Gothic vaults, an ornate carved ceiling and a mystical labyrinth that leads believers to Jerusalem.
Other finery includes 19th-century Swiss stained-glass windows, 14 side-chapels devoted to saints, and a collection of ecclesiastical objects (which can be seen on Saturday afternoon guided tours between June and September).