Assertion: castle's keep | /r/HasProperty | flanked by four rounded bastions
Facets:
Source sentences:
text: Walmer Castle retains most of its original 16th-century structure, with a tall keep, 83 feet (25 m) across, at the centre, flanked by four rounded bastions, one of which served as a gatehouse, and a moat, surrounded in turn by a curtain wall.