Narrow house = low tax, wide house = high tax. In the old days, that was the way it was in Amsterdam and that's the explanation to why many houses are narrow, tall and deep.
This is a photo from the neighborhood in Amsterdam's main red light district.
There are three RLD in Amsterdam. The main area is in the Walletjes area (between Centraal Station and Nieuwenmarkt). The other two in Singel (between Raadhuistraat and Centraal Station) and de Pijp (behind the Rijksmuseum).