Troyes rewards slow wandering. The old town is shaped — genuinely — like a champagne cork, and its medieval street plan is extraordinarily intact. Start at the Cathedral of Saint-Pierre-et-Saint-Paul, the city's headline sight, and allow a full morning for it — the stained glass alone justifies the trip. Then work outward through the old town's half-timbered streets, ducking into the narrow bouchons (covered passageways between buildings) that link the main streets.
The Musée d'Art Moderne holds one of the finest Fauvist collections in France, assembled by a local couple and donated to the city. Serious art lovers should not skip it. The Cité du Vitrail, opened in 2021 in the former Hôtel-Dieu, takes a deep dive into the history and craft of stained glass — essential context if you want to understand what you're looking at in the cathedral and churches.
Beyond the Basilique Saint-Urbain — one of the purest examples of Rayonnant Gothic in France — there are eight more medieval churches in the old town, each with its own glass. The Église Sainte-Madeleine has the only surviving stone rood screen in France; the Église Saint-Pantaléon is essentially a storage museum of sculpture moved here from demolished churches. You could spend days just on the churches.