The Spanish, meanwhile, had their own impressive fortified cities. Toledo is famous for its beautiful cathedral, but the medieval walls are an interesting sight too. The city used to be the center of the Spanish Empire, under the Visigoths, and so good defenses were essential. Toledo had natural advantages – it was sited on a hill and had a river on three sides, so the walls only needed to cover one side. It was always a cultural melting pot, with Christians, Jews and Muslims mixing within its walls and it is now a UNESCO World Heritage Site, due to its outstanding architecture.