Bangkok is famous for its canals or khlongs with tourist brochures promoting the city as having once been "The Venice of the East". In fact the history of Thailand's canals is older than Bangkok itself. The "Venice of the East" description was originally from the Portuguese explorer Fernão Mendes Pinto writing about Ayutthaya in the 1540's. But why were there so many canals, when were they built and why are they to blame for Bangkok's terrible traffic-jams today?