Abbaye de Forest is the remnant of a Benedictine abbey founded as a women's priory in the 12th century. Fire, suppression, and rebuilding left a mixed historic complex rather than a complete medieval abbey, but the surviving buildings still give Forest a deeper history than most visitors expect from Brussels' southern suburbs.
It is best treated as a short architectural and historical stop while exploring Forest or Saint-Gilles, not as a headline Brussels sight. The exterior and surrounding area are the main draw unless an event or opening gives access inside.