Three thousand years ago, stone towers — often surrounded by settlements enclosed within stone walls — peppered the Sardinian countryside. There were an estimated six to seven thousand of these towers constructed in the period roughly between 1600 and 550 BC, the Bronze and Iron ages in Sardinia. Perhaps many more still lie undiscovered beneath the ground or covered by earth mounds.

These stone towers are called nuraghi (singular, nuraghe), and they have become identified...

The last thing I expected to find in the French Riviera city of Nice was the ruins of a 2,000-year-old Roman city. The Mediterranean, miles of beaches, the famous Promenade des Anglais adjacent to those beaches, yes. Several fabulous art museums, certainly. Cafés, bistros, restaurants, of course. But a Roman city just a few miles from Nice's alluring beachfront was a surprise.

Located in the upscale residential area of Cimiez in Nice, with villas set in lush gardens, what was once...

The city of Salalah lies on the southern coast of Oman beside the Arabian Sea, about 600 miles southwest of Muscat, the country's capital. It is in this area of Oman that the frankincense trade flourished for hundreds of years, beginning perhaps as early as the third millennium BC.

From ports along Oman's southern coast, frankincense traveled by land and sea not only to other parts of Oman and the Arabian Peninsula but east to China and India and north and west to Mesopotamia...