Basilique St-Sernin Toulouse St. Serenan Cathedral is the most complete Roman architecture preserved in France. Grand spectacle, up to 115 meters. Above the Church of Christ is an octagonal tower built in the thirteenth century, one of the peaks of medieval religious architecture. Opening hours are 8:30-18:15 from July to September, 8:30-19:30 from Sunday, 8:30-11:45 from October to June, 14:00-17:45 from Monday to Saturday, 8:30-12:30 from Sunday and 14:00-15:30 from June to Saturday. Free visit. It's about 15 minutes'walk from the railway station.