Porte de Bourgogne

This guide to the Porte de Bourgogne in Bordeaux starts with a puzzle underfoot: why this eighteenth-century triumphal arch looks like it is sinking into its own square. It traces the site back to salt marshes worked by tides off the Garonne, and to the Marquis de Tourny's plan for travelers arriving from Paris, an arch raised by the architect Andre Portier. From there it follows the awkward engineering problem that the later Pont de Pierre bridge created for this same gate. Look down at the base before you look up at the arch.