12901623 - Bastion at the angle of London Wall, City of London, 177912904240 - Roman bastion on the city wall, London, 4th century11666486 - Capture of a bastion at Troyes13359358 - Fort Ticonderoga, New York12915740 - Fortifications, c188012504693 - Valletta, Malta12504689 - Mdina, Malta12394767 - Siege Technology11717393 - Am Buachaille sea stack,UK11717689 - A man on the cliff tops at Boscastle,UK11655281 - Belidor's Ravelin fortification methods11660253 - Siege of Brest11653980 - Kent artillery fort,16th century11655323 - Comparison of Fortification Systems11655298 - Coehoorns Fortification Methods11655324 - Fortification Methods11655253 - Muller's Fortification Methods11632516 - New York City and docks,19th century