Marvel at the size of Nantes Cathedral. Go to a service if you can or just take a seat and enjoy the peace and quiet.
If you've got time to stop for a while in Nantes Centre, Nantes Cathedral is a good place to kick off your sightseeing. This principal church is one of many attractions that'll keep you on the go here. Zenith de Nantes, Chateau of the Dukes of Brittany, and Passage Pommeraye are also ready to be explored nearby.