While admittedly the single most impressive Roman structure in Tuscany is the theater of Fiesole 5 miles north of Florence that’s still in use today, the silent, glorious hilltop of Cosa with unlimited views up and down the coast and to the Argentario Peninsula, is one of the most stunning and rarely visited of Roman sites. The Romans used subjugated Etruscan craftsmen to build the town—the perimeter wall, still intact, is as impressive in the sizes and fits of the stones as any of the Incas’. The town layout gives a ready glance into Roman daily life. The small archeological museum is a gem, and near it are the remnants of an elegant, multi-leveled Roman villa. At the tip of the promontory, stand the ruins of a medieval castle (some walls and the prison pits still intact) built by the Aldobrandschis in 1269 and destroyed by the Siena in 1329. Be warned: there is no food nearby so pack a feast of a lunch. The ancient olive grove alone is worth the trip.