Nestled in the bucolic Authie valley 27km northeast of Le Crotoy, this strikingly beautiful 12th-century abbey, rebuilt between 1687 and 1756, merits a detour for its harmonious Cistercian architecture and Baroque interiors. One of northern France's most intact old monasteries, it retains its cloister, sacristy, chapter house and refectory. The church has a magnificent organ loft and a wrought-iron choir screen. Covering 8 hectares, the landscaped gardens have over 5000 plants including rare apple trees and roses.
The complex has been owned since the 1920s by a not-for-profit association that still runs foster and nursing homes on the premises, which is why visitors must join a guided tour; call ahead for details on English tours. Year-round, the abbey welcomes overnight guests in 16 large, simply furnished rooms and suites; singles/doubles/suites start at €65/70/110. The on-site restaurant serves dishes using organic produce from the kitchen gardens and can arrange picnic baskets.