PARIS (AP) — For weeks, a black mountain loomed over the Seine where Paris’ oldest bridge should have been. On Monday evening, its doors finally opened. Inside, Paris smells different. The air carries the scent of earth after rain — damp ancient stone, cellar walls, perhaps a trace of smoke. Visitors step from the bright riverfront into a dark passage lined with glowing photographs of caves, as a low electronic pulse seems to breathe through the walls. Beneath it all, the old of the Pont...