There is an old adage that “all roads lead to Rome.” It’s a statement with much truth in it, since most, if not all, roads in the early centuries of the Christian era did lead to Rome, then the center of a vast, far-flung empire.

The same adage could be applied to 14th-century Tenochtitlán, then the center of the Aztec empire in Mesoamerica. All roads seemed to lead to Tenochtitlán. Or at least they did from AD 1325 to 1521.

Before then, the Aztecs...

During the 1940-1941 Blitz, much of the area called The City, London’s historic center as well as its central business district, was destroyed. Years after the end of World War II, bombed-out sites were still being excavated. In 1952-1954, one of these sites, located on Walbrook between Cannon Street and Queen Victoria Street in the heart of The City, yielded a remarkable discovery buried 23 feet below the surface: the remains of a Roman temple.

On the last day of the excavation...

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...