Beaune is still encircled by its 15th-century defensive walls — a complete ring of towers, bastions, and earthen ramparts that gives the town its distinctively tidy, self-contained feel. You can walk the full circuit in about half an hour along the chemin de ronde that runs behind the walls, looking inward over rooftops and church spires or outward toward the vineyards that begin directly outside the gates.
The ramparts were built to a design that proved ahead of its time — the low earthen bastions were designed to absorb cannon fire rather than resist it, and Beaune was consequently never successfully besieged. Today the most visible section is along the south, where the semicircular towers have been absorbed into the wine trade they were built to protect.
Several négociants offer cellar visits from entrances in or near the old walls, so the walk is not just a defensive-history loop. If you only have time for one underground visit, Patriarche Père et Fils is the showpiece: five kilometres of vaulted cellars beneath the former Carmelite convent, with a self-guided tasting route that is touristy but genuinely impressive.