The Fort Veldhuis is part of the defense line of  Amsterdam. The army, the government and the  king/queen would be within the ring to withdraw from  an attack on the Netherlands.   The Defence line consists of 46 forts and batteries,  dikes and sluices at a distance of 15 to 20 kilometers  from Amsterdam.  The idea behind the Defense line of Amsterdam is an  example of Dutch hydraulic engineering ingenuity.   With an ingenious system, the country around the  board be put under water, which could create a pond,  not deep enough for ships but too deep for man and  horse. Before the theorem was completed, it was  already out of date. The rise of the airplane made the  system useless. During the two world wars, the defence line is in a  state of operation but had never actually used as  such. Meanwhile, a large number of forts bave a new  purpose. Since 1996, the Defence Line of Amsterdam is placed  on the UNESCO World Heritage list next to for  example, the Chinese Wall, Mont Saint-Michel and the  Pyramids of Giza  Fort bij Veldhuis Bron: