Strasbourg Cathedral (Notre-Dame de Strasbourg)
Built mostly between the 12th and 15th centuries, the cathedral's single spire made it the tallest building in the world for over two centuries after its completion in 1439 (the second tower was never added). The pink Vosges sandstone facade is covered in tiers of statuary, and inside, the 16th-century astronomical clock draws a crowd each day for its mechanical procession of the Apostles.