An uncultivated and insalubrious region extends, likewise, along the sea to the south of the Tiber. Poisonous vapours arise from the stagnant waters separated by dunes from the sea, and in order to escape them it is necessary to seek a refuge in the hills of the interior, or even on jetties built out into the sea, as at Porto d’Anzio. The palaces which formerly lined the shore from Ostia to Nettuno, and from the ruins of which have been recovered some of our most highly valued art treasures, such as the Gladiator and Apollo Belvedere, have been buried long ago beneath the dunes or in the swamps. The most dreaded of these malarial districts lies at the foot of the Monti Lepini, and extends from Porto d’Anzio to Terracina. It is known as the Pontine Marshes, from Pometia, a city said to have perished before historical times. No less than twenty-three cities formerly flourished in what is now a deserted and deadly country, but which was the most prosperous of the districts held by the confederation of the Volsci. The Roman conquerors created “peace and solitude” at the same time. Four hundred and forty years after the building of Rome, when Appius constructed his famous road to Terracina, the country was only a swamp. Various attempts have been made since to reclaim this region, but it still remains the haunt of boars, deer, and semi-savage buffaloes, whose ancestors were imported from Africa in the seventh century. The canals dug during the reign of Augustus appear to have been of little use; the works undertaken by Theodoric the Goth were more efficacious; but stagnant waters and malaria in the end regained the mastery. The engineers employed by Pius VI. towards the close of the eighteenth century failed likewise, and this district of 290 square miles remains a wilderness to the present day. If a brigand seeks refuge in it, pursuit is stopped, and he is allowed to die in peace. [Illustration: Fig. 95.—THE PONTINE MARSHES. Scale 1 : 280,000.]