Annaschnitfink's Fotothing

Holland Penningsveer, mun. Haarlem
Fort Penningsveer (and the river the Liede)
is also part of the:
Stelling van Amsterdam or Amsterdam Defense Line. The city of Amsterdam (Holland's capital) is surrounded by a chain of forts, dams and sleuzes with a length of 135 kilometer. They were built in a very short period (in between 1880 and 1914) after the French-German war of 1870-1871. Their purpose was to protect Amsterdam. The principal idea was to flood the land surrounding Amsterdam. In a military sense the chain of fortifications, dams and sleuzes was 100 % effective, it was impossible to break through this defense line, until ... the arrival of aeroplanes. By this the whole system became completely and totally obsolete. Since it is a unique defense system in this part of the world it was put on the Unesco World Heritage List in 1996.
If you want more info:
http://www.stelling-amsterdam.org/english/index.htm
The info on this site is in Dutch and in English
De info op deze site is in het nederlands en in het engels.