Once being in Strasbourg to visit the Christmas market of course you should take a closer look to the famous Munster, the landmark of Strasbourg. The Strasbourg Munster, also in French Cathédrale Notre-Dame de Strasbourg is a Roman-Catholic church and is one of the most important cathedrals of the European history of architecture.
The munster was built from 1176, after finishing the northern tower (ca 140 meters height) in 1647 until 1874 the munster has been the highest building ever. If there's no Christmas market you have the possibility to climb the stairs of an outside spiral stairway up to the top platform. Only to recommend for people who are not scared of heights...
Inside you can enjoy the colorful round shaped windows, the old organ and the extraordinary size of the hall.