The Tour de la Lanterne is the third of La Rochelle's harbour towers, built at the end of the 15th century as a lighthouse, prison, and refuge for the watchmen of the port. The slim, octagonal spire and pointed roof give it a more fairy-tale shape than its squat older neighbours.
The interior is the most evocative of the three towers. Generations of sailors and pirates were locked up here, and the walls are covered in graffiti — ships, dates, names — scratched into the limestone over centuries. Climb to the top for a long view east over the rooftops of the old town and west across the open Atlantic. The combined ticket with Saint-Nicolas and the Chaîne is the best value.