Basilica of Saints Nazarius and Celsus vs Carcassonne Cathedral
Two churches in Carcassonne. Basilica of Saints Nazarius and Celsus has no online ticket listed; Carcassonne Cathedral has no online ticket listed. The table and the two notes below put them side by side; the full pages have what to see, the ticket and the timing for each.
The basilica stands inside the walled citadel of Carcassonne, at its southern end, a few minutes on foot from the castle keep. Entry is free and no booking is needed, which makes it the best value inside the walls by a wide margin, since almost everything else there is either ticketed or a souvenir shop. Guided tours of the citadel include it as a stop, and the good ones spend time on it, because the church explains the history of the site better than the restored ramparts do.
Almost everyone who visits Carcassonne goes to the walled citadel on the hill and never learns that the cathedral is somewhere else entirely. Saint-Michel stands in the lower town, the grid of straight streets laid out in the thirteenth century after the old suburbs were destroyed, about twenty minutes on foot from the Cite across the river. Entry is free and no tour is needed.