Complex sentence: It is noted for its 13th-century cathedral on the site of the original founded by Saint Paul Aurelian in the 6th century and the Notre-Dame du Kreisker Chapel, an 80 m high chapel, which is the highest in Brittany.
Split into simpler sentences: It is noted for its 13th-century cathedral on the site of the original founded by Saint Paul Aurelian in the 6th century. It has kept a unique architecture, such as Notre-Dame du Kreisker Chapel, an 80 m high chapel, which is the highest in Brittany.