Founded in 1225 by William Marshal, this Dominican abbey takes its name from the monks' black habits. Much of what survives dates from the 18th and 19th centuries, but remnants of more ancient archways are still evident, and the stained glass is glorious. When services are not being held (check the website for Mass times), you can pick up an information leaflet in exchange for a donation and explore; look for the 13th-century coffins near the entrance.