The nucleus of the Dacian kingdom was to be found in the Orastiei Mountains in the south west of Transylvania. The Dacian Fortresses built in the 1 st century BC and the 1 st century AD, which are preserved at the edge of these mountains are among the few vestiges of these legendary ancestors of the Romanians, who considered themselves "immortals". These fortresses, enclosed by perfectly fitting these walls of polished limestone blocks, represent a defensive system unique in European architecture. Countless forts, strategic constructions and watchtowers cover a 200 sq km area of the Orastiei Mountains. The numerous sanctuaries discovered in their vicinity are a testament to the profoundly religious spirit of this mysterious people, about whom few things are known with certainty. The original combination of religious and military architectural elements characterizes these citadels from the classical phase of Dacian civilization.

The military, political, economic and religious center of the Dacians was Sarmisegetusa Regia. Ot os situated 1200 meters above sea level, at the highest point of Gradistea Hill in the commune Orastioara. Many manmade terraces were carved out of the hillside. The upper plateau is connected to the sacred area of the sanctuaries on two terraces by a sacred way - a monumental paved road with limestone flags. Before it was conquered and destroyed by the Romans, Sarmisegetusa was the most important metallurgical center anywhere in Europe outside the Roman Empire.

All the access routes to this capital were protected by numerous other strategically placed citadels. These include: