This area has been characterised, since ancient times, by the contrast between large rural extensions and city centres with high concentrations of residents. Around the historic centres, already considerably large and densely populated, the cities have expanded in a compact way. The design of the cities, quite complex and composite, reflects in the conformation of the streets, the guiding criteria of the various dominions and cultures that have ventured into the territory. Therefore, there are examples of the tortuous course of the Arab layout, the orthogonal Medieval type, the radial style of the Enlightenment, the wide streets and tree-lined plazas of the 1800's and the city parks of the early 1900's.
The majority of the centres had imposing Norman-Swabian city walls, often with very imposing towers and doors which were, wholly or partially, destroyed from the 1700's on, to make room for new buildings. The wall moats were generally filled and the cities' first ring roads were built on their tracks. A visit to the historical centre of each of these cities will reveal, besides the monuments, a great homogeneity and optimum preservation of the buildings, which are valuable because of the generalised use of local stone and tufa – the same materials used in the most ancient and noblest monuments – not only in all of the houses, but also in the pavements, which are often still today paved with the original flagstones of Trani stone. The modern cities join the network of productive areas, which are all located on the main roads that lead out of the cities