One #vuurtoren or light tower is a tower that was built near cliffs, or directly on it, straits, entrances to sea arms and ports to warn ships at night and in stormy weather of the cliffs or passage, originally using an open fire and later by means of mirrors, lenses and a lamp.
Ports or port channels also sometimes have one or more lighthouses that indicate access and often form a line of light.
Along the Dutch coast there are eleven large lighthouses (so-called A posts) and four smaller ones (B posts). In addition, there are five more towers on the banks of the IJsselmeer.

Lighthouse Of Urk: