Immerse yourself in history in Cartagena, which was founded in 220 BC. It’s in southeast Spain’s Murcia region, and has been used as a defensive port for thousands of years. You’re spoilt for choice when it comes to ancient Roman ruins on Cartagena cruises: we’d start at the Casa de la Fortuna – which was once the home of a wealthy Roman family and dates back to the first century AD. Learn more about the city’s fascinating Roman history by visiting the Museo del Teatro Romano. Cartagena is one of those cities which rewards an afternoon spent getting lost. The centre unravels beneath your feet to reveal photogenic Modernist architecture (don’t miss the century-old town hall on the Plaza del Ayuntamiento or the Casino de Cartagena). Take a walk along the picturesque Calle Mayor as day fades into night to drop in at a tapas bar or simply to admire the distinctive blue tiles underfoot. No visit to Cartagena would be complete without a visit to the Battery Castillitos – travel for just 30 minutes outside the city to find yourself surrounded by an eerily beautiful world of dust and stone. There’s an installation here that was built during the 1930s, and which combines medieval turrets and artillery guns to arresting effect.