Cropmarks of a possible prehistoric henge, to the south-east of Calceby. The site appears on aerial photographs as a very broad-ditched circle of perhaps 50m overall diameter, with a single wide gap to the east. An alternative explanation as the remains of a former mill mound have also been suggested, due to its proximity to the medieval settlement remains at Calceby, though a group of probable Bronze Age barrows also lay to the south, which may be associated. {1}{2} The feature has also been noted on aerial photography examined as part of the National Mapping Programme. It measures roughly 40m in diameter overall, with an internal diameter of roughly 20m. The exact origin and identification of this features remains uncertain, though the interpretation as a possible henge is thought to be less likely. {3}