Beside Ratchadamnoen Road, roughly dividing the modern city center from the now mostly residential old city is a reconstructed piece of the old city walls. The brick walls were built in the thirteenth century to replace old earthen ramparts and enclosed a rectangle 400 meters wide and 2,230 meters long.
The city walls and north gate
The story goes that bricks from the old wall were used to build the town prison, which used to stand across the street from the reconstructed gate. The prison has now itself been torn down and turned into a park. Only a few guard towers remain to let you know the prison was there.