Like its neighbours, Sukhothai and Si Satchanalai, with whom it formed the kingdom of Siam, Kamphaeng Phet was a fortified city. The town takes its name, which means “Walls of Diamond”, from its fortifications which form a long trapezium running parallel to the River Ping. The walls here have stood for centuries, protecting an archaeological World Heritage Site which includes two museums and two major temples. Unfortunately, the royal palace, built entirely of wood, has not survived.