The Carthaginians founded the city in 223BC and named it Cartago Nova; it later became a prosperous Roman colony, and a Byzantine trading centre. The city has been the main Spanish Mediterranean naval base since the reign of King Philip II, and is still surrounded by walls built during this period. Cartagena’s importance grew with the arrival of the Spanish Bourbons in the 18th century, when the Navidad Fortress was constructed to protect the harbour. In recent years, traces of the city’s fascinating past have been brought to light: a well-preserved Roman Theatre was discovered in 1988, and this has now been restored and opened to the public. During your free time, you may like to take a mini-cruise around Cartagena's historic harbour: these operate several times a day, take approximately 40 minutes and do not need to be booked in advance. Full details will be available at the port.