Longpont, which lies just outside the Retz Forest, is known for the imposing ruins of its church and the buildings of this Cistercian abbey founded by St Bernard in the 12C. The four fine conical turrets of the 14C fortified gate, a vestige of the original enclosure, are the first thing to catch your eye upon leaving the forest. The buildings, which were reworked in the 18C, are complemented by interior gardens that open onto the park and ponds. Be sure to see the monks' heated room (13C), whose chimney stack is supported by four pillars.