Forte San Giovanni was built between 1640 and 1644 just above the point where the valleys of rivers Pora and Aquila meet with the aim of strengthening defenses. The fort was adapted to the geographic topography and enclosed the ancient medieval tower linking the Finalborgo walls on Becchignolo hill. The work was directed by Ferdinando Glazer. This tower was recorded by the historian Filelfo and portrayed in a drawing of 1571.
The building developed with a pincer-shaped façade facing south, with high crowned walls with no openings, surmounted by a low parapet, and with suspended look-out towers on each corner. The fortress underwent other modifications directed by Spanish engineer Gaspare Beretta between 1674 and 1678. It was abandoned by the Spanish in 1707 and, under the domination of Genoa in 1713, it was partially destroyed. In 1833 it became a prison.
Since 1960 it has been public property and it has recently been completely restored.
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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.