Orbetello makes a threatening front to the stranger. A strong line of fortifications crosses the sandy isthmus by which he approaches it; principally the work of the Spaniards, who possessed the town for a hundred and fifty years—from 1557 to 1707. On every other side it is fenced in by a stout sea–wall. But its chief strength lies in its position in the midst of the wide lagoon, protected from all attacks by sea by the two necks of sand which unite Monte Argentaro to the mainland ; and to be otherwise approached only by the narrow tongue, on whose tip it stands—a position singularly like that of Mexico.

This Stagno, or lagoon, the “sea-marsh” of Strabo, is a vast expanse of stagnant salt-water, so shallow that it may be forded in parts, yet never dried up by the hottest summer; the curse of the country around, for the foul and pestilent vapours, and the swarms of musquitoes and other insects it generates at that season, yet blessing the inhabitants with an abundance of fish. Orbetello has further interest for the antiquary. The foundations of the sea-wall which surround it on three sides, are of vast polygonal blocks, just such as are seen on many ancient sites of Central Italy—Norba, Segni, Palestrina, to wit—and such as compose the walls of the neighbouring Cosa.