Cairo, Egypt, in its history[?] has had a significant number of fortified gates protecting both inner and outer city. Apart from the purpose of defense they were also used for differentiation of the varied social and economic classes. Often the gates were heavily decorated as artistic pieces.
... Tate Britain and Tate Modern
Victoria and Albert Museum
Merseyside
Customs & Excise National Museum[?]
Historic Warships[?], Birkenhead
Lady Lever Art ...