Gates 1/4: The Weighhouse on the Nieuwmarkt in Amsterdam.
The weighhouse was originally part of the medieval fortifications of the city. It was build as a city gate: St.Antoniespoort (St.Anthony's gate). After the cities expansion of the 17th century the building lost its function as city gate and became the weigh house. Besides witches they weighed many other things like ducks. The top floor of the weigh house was used by several guilds. The guild members didnt want to share an entrance gate with the other guilds so each guild was designated another entrance (see next image)
http://www.bma.amsterdam.nl/adam/nl/groot/waag.html (dutch)
http://www.bma.amsterdam.nl/adam/uk/stadsgeb.html (english)