Not only the Dam Palace is built on wooden poles, but the whole city of Amsterdam is. The reason for this is that the soil of Amsterdam consists of peat on which the construction of houses and buildings is impossible. A foundation of wooden poles made it possible to built a whole city!
There is even a Dutch rhyme about this:
Amsterdam, die grote stad,
Die staat op honderd palen,
En als die stad eens ommevalt,
Wie zal dat betalen?
