The photos are of a Huers Hut overlooking the sea at Newquay, Cornwall. It is said to date from the 14th century - but could well be older - and was used as a look-out when shoals of pilchards were expected in the bay.
The huer would sound his horn raising a hue and cry alerting townsfolk to the arrival of the fish.
By means of hand signals the huer enabled the fishermen to position their boats and encircle the shoals into their nets.
Previous to being used by a Huer the hut may have been a hermitage. Externally the building has a large, typically Cornish, late medieval chimney and a narrow stairway leading to the roof.
Though I have used the words hue and cry above there are other suggestions as to how the phrase originated. Wikipedia, for example, suggests the following:
By the Statute of Winchester of 1285 it was provided that anyone, either a constable or a private citizen, who witnessed a crime shall make hue and cry, and that the hue and cry must be kept up against the fleeing criminal from town to town and from county to county, until the felon is apprehended.
See also : Newquay Harbour in 1875 and 2019