Heritage Days beckon this weekend, September 19–20, 2026, for its 43rd edition. In Paris and the Île-de-France region, it’s a chance to visit museums and châteaux for free, to explore sites opened specially for the occasion, to join quirky guided tours, and to enjoy other engaging activities, centered on the themes “Heritage in Peril: Revive, Resist, Reimagine” and “Heritage of Photography.”