These poles are significant representatives of our Dutch inheritance.
You may find them alongside the entire coastline at every hundred meters.
For hundreds of years the Dutch people relied on these numbered coastal objects for orientation, defence and warning whenever the water level raised too high.
To know where a ship was in trouble, loot was washed ashore or bathers needed help from the coast guard. Before the cell-phone was invented small children had the number
written on their arms in case of wandering off.
They had a significant purpose even during WW2 in military tactics.