Palais Gallien is all that survives above ground of Roman Burdigala — two partial arched sections of a 3rd-century amphitheatre that once held 15,000 spectators. The ruins stand in a small urban park in the Saint-Seurin neighbourhood, somewhat marooned among residential streets, which makes them feel genuinely ancient in a way that a more polished site would not.
The site is compact and takes twenty minutes to walk around. It is free to enter. At night, when it is lit up, the arches have a picturesque quality. There is information board context in French and English. This is decidedly a for-enthusiasts site rather than a major attraction, but anyone interested in Roman archaeology will find it worth the detour.