Hadrian's Library was created by Roman Emperor Hadrian in AD 132 on the north side of the Acropolis of Athens.
The building followed a typical Roman Forum architectural style, having only one entrance with a propylon of Corinthian order, a high surrounding wall with protruding niches (oikoi, exedrae) at its long sides, an inner courtyard surrounded by columns and a decorative oblong pool in the middle.The library was on the eastern side where rolls of papyrus 'books' were kept. Adjoining halls were used as reading rooms, and the corners served as lecture halls.
The library was seriously damaged by the Herulian invasion of 267 and repaired by the prefect Herculius in AD 407-412. During Byzantine times, three churches were built at the site, the remains of which are preserved: a tetraconch (5th century AD), a three-aisled basilica (7th century) and a simple cathedral (12th century), which was the first cathedral of the city.
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.