The Batterij 3 in linie Kudelstaart – Uithoorn is a Unesco protected monument. It is one of several forts along a defensive line which was constructed at the end of the 19th century. The forts were usually unmanned during peacetime, but in times of need, they could be used to quickly cut off important access-ways such as railroads and waterways. When needed, the defence lines could ensure the polders were flooded just enough to be too deep for infantry, but too shallow for boats.
