The old section of Chinatown in Bangkok before it expanded east toward Yaowaraj road originally began at Sampaeng (Soi Winit 2) near where the memorial bridge connects the city with Thonburi. I came across an old photo taken at the turn of the last century and found that I had inadvertently taken a photograph from the exact same spot.
Saphan Han just east of Pahurat lies at the Rob Krung Canal near Yaowaraj. I believe the original photo was taken in 1902. This canal today is absolutely putrid.
You can see many homeless people defecate into the same water that their brothers and sisters will fish from.
The large monitor lizards who rule these areas don't seem to mind.
Eric from Tour Bangkok Legacies has a great post with photos on this neighborhood and the market which also bears the bridge's name: Saphan Han the dragon's tail in Chinatown Bangkok.