It seems counterintuitive, but sometimes archaeologists can learn more by not digging up the past. In fact, noninvasive methods—including lasers, ground-penetrating radar, and drone photography—are changing the way they do their work.

One of the latest examples: a project at Ammaia, in southern Portugal, where researchers have been able to create detailed, three-dimensional illustrations of a now-underground Roman village in its heyday.

Data from the site show that the town flourished in the first century A.D.—at its peak it was home to more than 2,000 inhabitants—but gradually declined in the fourth century. By the Middle Ages it was abandoned.

Using a variety of noninvasive techniques, an international team of researchers has been able to identify different phases of the town’s construction, from