White stone villages, troglodyte houses and views of the Adriatic Sea: this is the perfect itinerary for a road-trip in Puglia, the treasure of southern Italy.

All maps are influenced by the intent and biases of their creator—even those that are striving to be as accurate as possible.

Fabio Portella, a professional diver who has worked with marine archaeologists for years, was surveying the seabed near ...