Conwy's town walls are a medieval defensive structure around the town of Conwy in Wales. The walls were constructed between 1283 and 1287 after the foundation of Conwy by Edward I, and were designed to form an integrated system of defence alongside Conwy Castle. The walls are 1.3 km (0.81 mi) long and include 21 towers and three gatehouses. The project was completed using large quantities of labourers brought in from England; the cost of building the castle and walls together came to around £15,000, a huge sum for the period. The walls were slightly damaged during the rebellion of Owain Glyndŵr in 1401, but political changes in the 16th century reduced the need to maintain such defences around the town. The fortifications were treated sympathetically during the development of the road and railway systems in Conwy during the 19th century and survived largely intact into the modern period. Today the walls form part of the UNESCO world heritage site administered by Cadw. Historians Oliver Creighton and Robert Higham describe the defences as "one of the most impressive walled circuits" in Europe.