During the Anglo-Russian invasion of Holland in 1799, Cornelis Krayenhoff protected the capital by erecting the "Linie van Noord-Holland" ("North Holland Line"). He flooded the lower-lying areas between Monnickendam and Krommeniedijk, and protected the higher situated areas using earthen walls and field artillery. A year later, Krayenhoff oversaw the construction of a second defensive line, west of Amsterdam, the "Linie van Beverwijk" ("Beverwijk Line"), consisting of three lines of lunettes. The lunettes were spaced at a distance of 400 metres from each other. Ten of these lunettes still remain.