In Amsterdam in 1966 Henriette van Weelde took in a stray cat and her kittens. People began to drop off rescued cats at her doorstep and she couldn't turn them away. After 2 years Henriette ran out of room to house more cats so she put them all on an unused houseboat on the nearby Herengracht canal. The feline sanctuary was a ‘pirate’ ship for about two decades, operating without the knowledge of the authorities. But in 1987, it finally got a permit and was officially christened ‘de Poezenboot’ (the Cat Boat).
"The rescue boat served as a safe haven for cats in Amsterdam for decades, with Henriette caring them until her death in 2005. It is now run with the help of a small staff and a few local volunteers. On any given day, you can find around 50 cats lying around the ‘world’s only floating cat hospital’, of which at least 14 are permanent residents. The others can be adopted."
More: Oddity Central