Reims is one of the oldest cities in France, dating back to Roman times. In 5th century Frankish lord Clovis was baptized in Reims by Rémi, bishop of Reims. It later became common to consider Clovis the first king of France. Consequently, most French kings were crowned in Reims.

The Cathedral of Notre-Dame de Reims was built in 1211 on the site of the original basilica where Clovis was baptized. The cathedral was damaged in WWII, and many of the original windows needed to be replaced. Some of the new stain glass windows were maid by Marc Chagall. The cathedral thus combines the modern and the new in a rather interesting way.

There is a good Wikipedia article about Reims.