Fortified with ramparts and parapets, this extraordinary 13th-century cathedral dominates the city. It was started as a building to strike fear into the hearts of the Albigensian heretics, 50 years after their defeat but it took 200 years to complete. It holds three records: it is the largest brick-built cathedral in the world, and it has the oldest medieval depiction of the Last Judgment (complete with devils and grimacing souls), and the largest surface area of Italian Renaissance frescos in France. It also has an exceptional restored 15th-century rood screen with unique polychromatic statues from the Old and New Testaments. It’s worth getting to the cathedral on Wednesdays at 5pm and Sundays at 4pm in July and August for a free organ recital.