The development and the prosperity era of the Dacian settlement on the Cetăţuia Hill - also that of whole complex of settlements in Orăştie Mountains - covers the period from Burebista to Decebal (1st century BC - 1st century AD). Destroyed after the second Roman-Dacian war and the conquest of Dacia by the Romans (105-106 AD), the fortress was never rebuilt.
Costeşti Fortress was the oldest and largest "dava" (fortress in Dacian) and is situated on the left side of Apa Grădiştei River, on the Cetăţuia Hill. Cetăţuia Hill with the fortress on its top form a great guard point, with large visibility, placed at the entrance of mountain range, where the valley suddenly narrows.
The defense system of the fortress was based on a sequence of three types of fortifications: a wave of earth, a stone wall 3 m thick, flanked by three towers and a double palisade surrounding the top of the height. The Dacian wall, built 2000-2500 years ago is perfectly straight and does not let any knife blade between its perfectly polished stones.
The highest plateau was occupied by two towers-house, built of stone blocks and bricks, barracks for soldiers and an observation tower. One can reach here climbing on the 'royal stairs', 3 m wide, made of andesite. The tens of andesite were artfully fashioned and endowed with incredible sewage channels.
The tower behind the stairs has cyclopic walls pointing to the solstice and is filled with big ilmenit bricks. On terraces were identified a tumulus on the southern part of the edifice, four sanctuaries, two water tanks and three isolated watchtowers guarding the antique access road.