Photo of Portchester Castle in Hampshire

Source: http://www.flickr.com/photos/20921249@N02/2389836862/, Flickr
Author: http://www.flickr.com/people/20921249@N02, scale speeder
Licence: Creative Commons Attribution 2.0 Generic

View of Portchester Castle in Hampshire.

Portchester Castle is a medieval castle built within a former Roman fort.

It is located at the northern end of Portsmouth Harbour.

Despite adaptation as a medieval castle, it is the best preserved Roman fort north of the Alps.