Alderney's 'Nunnery' is Britain's best preserved small Roman Fort. Its use continued through the Middle Ages, Napoleonic Wars, Victorian times and WW2.
Located at the western end of Longis beach the small fort, once known as Les Murs de Bas, or Lower Fort, and known today as the Nunnery, is, after recent archaeological investigations, now considered to be almost certainly Roman in origin. Its shape has striking resemblances to the five Roman so-called signal-station forts on the Yorkshire coast. This fort is the first evidence of military construction in Alderney. In addition the fort was used during the French Revolutionary and Napoleonic Wars, as a hospital and married quarters in Victorian times and was converted to a German strong point in the Second World War.