Fort Nieulay, located along the Avenue Pierre Coubertin, was originally dated to the 12th or 13th century. During the English invasion in 1346, sluices gates were added as water defences and a fort was built up around it in 1525 on the principle that the people of the fort could defend the town by flooding it. In April and May 1677, Louis XIV and Vauban visited Calais and ordered a complete rebuilding of Fort Nieulay. It was completed in 1679, with the purpose to protect the bridge of Nieulay crossing the Hames River. By 1815 the fort had fallen into a ruined state and it wasn't until 1903 that it was sold and improved by its farmer tenants. The fort was briefly the site of a low-key scuffle with Germans in May 1940.
References:The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.