The county's remarkable and richly varied military architecutre, from Hadrian's Wall to Warkworth, contrasts with monastic ruins buried deep in the valleys of the Coquet and the Aln or standing proudly by the sea at Holy Island and Tynemouth. Newcastle upon Tyne has the most elegant nineteenth-century city centre in England. Elsewhere the distinctive smaller towns include Alnwick, dominated by its castle, Hexham with its priory, brick-built Morpeth, and Berwick-upon-Tweed, ringed with exceptional sixteenth-century fortifications. Great country houses range from Vanbrugh's theatrical Seaton Delaval to Sir Charles Monck's austere Belsay and Norman Shaw's romantic Cragside. Monuments of a great industrial past, as well as a wealth of smaller buildings, such as bastle houses (peelhouses or stronghouses unique to the Border country), are all vividly described in this revised guide to Northumberland's architectural pleasures.