Surrounding the village of Lyons-la-Forêt, this vast woodland (10 700ha) is “one of the natural wonders of France and the apogee of the beech tree”. Its trees often have trunks over 20m high; the highest, the Bunodière beech, nudges 50m. Within its verdant expanse lie the former abbey of Mortemer and two interesting castles, at Fleury-la-Forêt and vascœuil.