Naples and its immediate surroundings preserve an archaeological heritage of inestimable value and among the best in the world. For example, the archaeological park of the Phlegraean Fields (Cumae, Baiae, the Flavian Amphitheatre and the Pozzuoli forum) is directly connected to the centre of Naples through the Cumana railway, and the nearby sites of Pompeii, Herculaneum, Stabiae and Oplontis are among the World Heritage sites of UNESCO.