Some time between 190 and 225, the Romans built the London Wall, a defensive ragstone wall around the landward side of the city. Along with Hadrian's Wall and the road network, the London Wall was one of the largest construction projects carried out in Roman Britain. The wall was originally about long, high, and thick. Its dry moat () was about deep and wide. In the 19th century, Smith estimated its length from the Tower west to Ludgate at about one mile () and its breadth from the northern wall to the bank of the Thames at around half that.