Around 4,000 years ago, a group of nomads in present-day Saudi Arabia constructed an “immense” network of defensive walls around a desert “oasis” where they eventually settled as a community.

The densely built city ... the defensive design of the walls. The authors concluded: "Topography thus played a decisive role in the siting of structures, as can be unambiguously seen around ...

The city of Parthenope was one of the earliest ancient Greek settlements on the coast of what is now Naples, Italy.