The Pillbox Study Group - Introduces the most common World War 2 defensive fortifications in the UK. Details the location, background information, history and other resources. - http://www.pillbox-study-group.org.uk/
Delaware's Coastal Defenses - History of Fort Miles and Fort Saulsbury and their role in defending the Delaware coast. - http://mysite.verizon.net/jeannekw/
UK World War 2 Pillboxes and Anti-Invasion Defences. - Photos of locations in the United Kingdom showing pillboxes and other defences built to resist a German invasion in World War 2. - http://www.pillboxesuk.co.uk
The Atlantic Wall - Features the history, original photos and tourist attractions of the German coastal defences in France 1940 - 1944. - http://www.atlantikwall.fr/language.htm
The Mannerheim Line - Photographs, drawings, tactical and historical descriptions of the Finnish fortifications that withstood the Russian offensive in the winter of 1940. - http://www.mannerheim-line.com/
Fortweb - Covers European fortifications of the 19th and 20th century, particularly the Maginot Line and Vallo Alpino in Italy. Contains photographs, history and weaponry information. - http://www.fortweb.net
Czechoslovak Fortification 1938 - Profile of the ultimately futile fortification systems constructed by the Czechs prior to the Nazi invasion. - http://www.rudolec.cz/forts/