Dug at the beginning of the 14th Century, this canal was the southern border of the city. Judging by its name, it must once have been a sewer. At the confluence of Oudezijds Voorburgwal, Oudezijds Achterburgwal and Grimburgwal the "house of three canals" can be admired; it was built in 1609. Its windows have the most pleasing design in the whole city, while its walls are a happy marriage of bricks and freestone. There are also two characteristic stepped gables.