All structures in Amsterdam are built on pilings sunk deep into soft soil. They get added reinforcement by being built adjacent to one another, so each building "leans" on the others in a block. These pilings can be made of wood because the muck they sit in doesn't allow oxygen to to break down the wood. Way back when, people used to put in their own pilings when building a house. Not everyone was good at it, nor did many have the resources to set big pilings very deep. So houses started to lean; then whole blocks started to lean.
So the government finally said "enough" and put in pilings themselves. They taxed residents to recoup the costs. The tax was based on how wide your house was.
So, of course, you built the narrowest, longest, highest house you could.
