Fortress

FOR003 - U-Boat Bases and Bunkers 1941–45

FOR004 - American Defenses of Corregidor and Manila Bay 1898-1945

FOR008 - Defenses of Pearl Harbor and Oahu 1907-50

FOR010 - The Maginot Line 1928–45

FOR015 - Germany's West Wall: The Siegfried Line

FOR023 - German Field Fortifications 1939–45

FOR027 - French Fortresses in North America 1535–1763: Québec, Montréal, Louisbourg and New Orleans

FOR028 - Forts of the American Frontier 1820–91

FOR069 - The Berlin Wall and the Intra-German Border 1961-89

FOR074 - Japanese Castles AD 250–1540

FOR097 - Colditz: Oflag IV-C

FOR105 - Forts of the American Frontier 1776–1891

FOR107 - Defense of the Third Reich 1941–45