Built from 1015 to 1439, Notre-Dame cathedral, a masterpiece of Gothic art, owes some of its charm to the pink Vosges sandstone used in its construction. The façade is remarkable, particularly the central portal. The Gothic spire, 142m high, is an architectural tour de force. From the 66m-high viewing platform, there is beautiful view of the city. Inside, don't miss the 12C-13C Angels' pillar, decorated with a group of Gothic statues, and the astronomical clock with its automated figures.