On Burgemeester Meineszlaan in Rotterdam is the post -museum, The national exhibition for Paal. This concise open -air museum (on the street) shows at a glance what the Netherlands Paaltjesland has in its march. Of course the pole with the most prestigious name is also in between: the diamond head pole. For me just as everyday as a 30 by 30 centimeters gray sidewalk tile, but thanks to his name it is also a bit the gem under the street furniture. It owes that name to the square beveled head, something that probably has been around since the Middle Ages. In the time that the diamond head pole was only made of wood, it made sure that the rainwater did not stay upside down and the pole would rot quickly. It is also handy that it is extremely uncomfortable to sit on the pole, essentially a subtle form of Hostile Architecture. Nowadays the beveled head is very subtle, but the shape is still doing its job. The wooden variant, even with reflector bands, is still on the market only almost three times as expensive. That is why the version of plastic is now dominant in the landscape. You see him solitaire regularly, but he comes into his own in groups. Often in long straight strips in succession to prevent cars or bicycles from driving somewhere where we do not want them as a society. The Mecca of the Diamantkoppaal is the Delflandplein in Amsterdam in the Netherlands. The entire square is lined there with a few and triple rows of diamond heads. They have been successful for years that scooters and cyclists make the square unsafe. For lovers of the Paaltjesmuseum in Rotterdam, definitely worth a trip.