A former Royal Observer Corps underground observation post was located to the east of Canwick. The post is believed to have been opened in 1961. Access was through a 2ft square hatch on the surface, where an associated air vent would have been visible. A ladder would lead down the concrete shaft to two rooms; the first being quite small and used to house the chemical toilet. The second, much larger monitoring room measured approximately 15' by 7'6'', and would have been staffed by three observers. The post remained in use until 1968, when it was closed and demolished shortly afterwards. {1} No elements of the post can be discerned on an aerial photograph taken of this area in July 1971, suggesting it had already been demolished by this time. Whilst the post is not extant, earthworks of a surrounding small enclosure within which the post would have been located can be identified, in the north-western corner of a larger arable field, to the immediate south of Heighington Road. {2}