Abbaye d’Aulne Wallonia

With origins in the 7th century, but destroyed post–French Revolution in 1794, this atmospheric monastery is a mixture of picturesque ruins, surviving 18th-century buildings and a later 19th-century convent church. The Cistercians ran the place in its heyday, when a sophisticated watercourse system ran around the complex. The skeletal remains of the Gothic church and the ruined cloister attest to the scale of what was once a thriving community. Signboards are in French, but you can grab an English guide from the kiosk.