The Church of the Trinity is located where a chapel was built in 1313. During the siege of the city by the troops of Louis XIV in 1684, the church and the 17th-century monastery surrounding it were destroyed. From 1737 to 1745, a new church was built on exactly the same spot and was the first large Baroque building in the town. Affected by the French Revolution, the church was transformed into a fodder store and as a theatre. Since 1817, it has been used for Protestant services.
The church of Saint-Michael was founded in 987 as the chapel of the castle of the Count of Luxembourg. Destroyed and rebuilt many times, the appearance of the present church owes much to its reconstruction in the 17th century, including the construction of the present tower (1648). The church has a beautiful listed organ dating from 1609.
Notre-Dame Cathedral is a church founded in the 17th century by the Jesuits. The church owes its current size and neo-Gothic style to a 20th century expansion. The crypt of the church contains the tombs of the grand-ducal family.