Founded in the 8th century BC, Naples is one of the oldest continuously inhabited cities in the world and a UNESCO World Heritage site. Its historic center is the largest in Europe and boasts a unique mixture of Greek, Roman, Norman, Angevin, Spanish, and French architecture. The city's setting on the Bay of Naples gives it an outstanding universal value, and its unmatched heritage as a place of exchange between cultures is reflected in its monuments and structure. Naples is also home to an unparalleled concentration of UNESCO World Heritage sites, including the Roman archaeological sites of Pompeii, Herculaneum, and Cumae, the Royal Palace of Caserta, and the Aqueduct of Vanvitelli. The city is close to Vesuvius, the only active volcano on the European continent, and is a favorite destination of the Roman poet Virgil.