The Basilique Cathédrale Sainte-Cécile d'Albi, commonly known in English as the Albi Cathedral, looks quite a bit different than most of the churches in France. First, it is made from clay brick instead of stone, giving it a pinkish hue rather than grey. Second and more noticeable still is the bell tower, which looks more like a fortress lookout than the usual intricately carved spires that visitors may be used to.
There's a reason for its fortified presence–it was built after the Church vanquished the Cathars, whose desire to create a new church was considered heretical. Although the site had housed other religious sites (including one that burned down in the year 666!), it is this one that has remained since its construction in the 13th century. Included on the grounds is the Berbie Palace, where bishops once lived and where the Toulouse-Latrec Museum sits today.
The Albi Cathedral is open from 8:30 a.m. to 6:45 p.m. every day from June to October. During the rest of the year, it closes from noon until 2 p.m. Entrance is free. Note that this is an active church, so it may be closed for religious services.