Amsterdam is built 800 years ago on a dried river mouth with a swampy bottom. The houses needed a deep foundation with wooden piles to prevent them from sinking. Some of the old piles are not in a very well condition anymore and the houses are leaning aside. They are not neglacted however, the city construction and housing supervisors keep an eye at the condition of the houses and sometimes they need to sustained.
These two at the corner are a bit out of balance so to see, but there has never a canal house fallen down before so I think it is all right the way it is.