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Photo: en:User:Geni, CC BY 2.5 via Wikimedia Commons
Fort Nelson, in the civil parish of Boarhunt in the English county of Hampshire, is one of five defensive forts built on the summit of Portsdown Hill in the 1860s, overlooking the important naval base of Portsmouth and is a Grade I Listed Building. The current tenant is the Royal Armouries, housing the artillery of the national collection of arms and armour.
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The castle's keep was built in Norman times (largely from recycled Roman brick) and extensive late Roman structures remain although ruinous. The castle is well sign posted, and served by regular buses, Portchester rail station is a 10-min walk north.