Stelling van Amsterdam - AbsoluteAstronomy.com

The UNESCO

UNESCO

The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...

A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...

known as the Defence Line of Amsterdam (in Dutch

Dutch language

Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

named Stelling van Amsterdam) is a 135 km long ring of fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

s around Amsterdam

Amsterdam

Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...

, consisting of 42 forts located between 10 to 15 kilometers the centre, and lowlands that can easily be flooded in time of war. The flooding was designed to give a depth of about 30 cm, insufficient for boats to traverse. Any buildings within 1 km of the line had to be made of wood, so that they could be burnt and the obstruction removed.

The Stelling van Amsterdam was constructed between 1880 and 1920. The invention of the aeroplane

Fixed-wing aircraft

A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

and tank

Tank

A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

made the forts obsolete almost as soon as they were finished. Many of the forts now are under the control of the town councils and the nature department, and may be visited. Monuments Day, on the second Saturday in September, is the ideal day to visit as entrance is free.

Function

The Stelling van Amsterdam was primarily a defensive "water line" (in Dutch: waterlinie). In the event of an enemy attack, large tracts of land around Amsterdam would be inundated with water, preventing the enemy from advancing. Amsterdam would function as a national reduit

Reduit

A reduit is a fortified structure such as a citadel or a keep into which the defending troops can retreat when the outer defences are breached...

, as the last stronghold of the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

. Forts were built where roads, railways, or dikes crossed through the water line. At such locations there would be no water to stop the enemy, and therefore the forts were intended to shell the enemy.

Construction

The law for the construction of the Stelling van Amsterdam was passed in 1874. During the preparations prior to construction, it became apparent that the design was already outdated by modern technical advances. The invention of the brisance grenade

Brisance

Brisance is the shattering capability of an explosive. It is a measure of the rapidity with which an explosive develops its maximum pressure. The term originates from the French verb "briser", which means to break or shatter...

(which would explode on impact of the target) necessitated the change from masonry

Masonry

Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...

to concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

forts. But the Dutch did not have the required experience yet using and building with concrete. Therefore extensive tests had to be performed where concrete structures were shelled with the heaviest artillery available at that time. Further delays resulted from the fact that the sand foundations had to settle for several years before the forts could be built on them. Not until 1897 could the actual construction finally begin.

Service

The Stelling van Amsterdam has never seen combat service and the use of aircraft rendered it obsolete after World War I. It was however maintained and kept in service until decommissioned in 1963.

The dike through the Haarlemmermeer

Haarlemmermeer

Haarlemmermeer is a municipality in the Netherlands, in the province of North Holland. It is a polder, consisting of land reclaimed from water, and the name Haarlemmermeer means Haarlem's Lake, still referring to the body of water from which the region was reclaimed in the 19th century.Its main...

, which made it possible to flood the southern portion of the polder

Polder

A polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity, meaning it has no connection with outside water other than through manually-operated devices...

while the northern portion could continue to produce food for Amsterdam, is now cut by the A4 Motorway

A4 motorway (Netherlands)

The A4 motorway is a motorway in the Netherlands from Amsterdam to the Belgian border near Zandvliet. Some parts of the motorway are still not completed. The completed route as of 2006 is divided into three parts: from Amsterdam via The Hague to Delft, from Vlaardingen to Pernis, and finally from...

. This motorway also goes under the Ringvaart

Ringvaart

The Ringvaart is a canal in the province of North Holland, the Netherlands. The Ringvaart is a true circular canal surrounding the Haarlemmermeer polder and forms the boundary of the Haarlemmermeer municipality...

at Roelofarendsveen, making flooding of the Haarlemmermeer Polder and future use of the Stelling no longer possible.

In 1996 the complete Stelling van Amsterdam was designated as a UNESCO World Heritage Site.

North front

Fort near Edam
Fort near Kwadijk
Fort North of Purmerend
Fort along Nekkerweg
Fort along Middenweg
Fort along Jisperweg
Fort near Spijkerboor

Northwest front

Fort near Marken-Binnen
Fort near Krommeniedijk
Fort along Den Ham
Fort near Veldhuis
Fort along the St.Aagtendijk
Fort in the Zuidwijkermeerpolder
Fort near Velsen
Coastal Fort near IJmuiden

West front

Fort North of Spaarndam
Fort South of Spaarndam
Fort near Penningsveer
Fort near the Liebrug
Fort along the Liede

Southwest front

Fort near Vijfhuizen
Battery along IJweg
Fort near Hoofddorp
Battery along Sloterweg
Fort near Aalsmeer

South front

Fort near Kudelstaart
Fort near De Kwakel
Fort along the Drecht
Fort near Uithoorn
Fort Waver-Amstel
Fort in the Waver-Botshol
Fort along the Winkel

Southeast front

Fort near Abcoude
Batteries along the Gein
Fort near Nigtevecht
Fort near Hinderdam
Fort Uitermeer
Weesp Fortress

Zuiderzee front

Muiden Fortress
Battery near Diemerdam
Fort along Pampus
Batterij near Durgerdam (Vuurtoreneiland)