Having an approximately trapeze-like shape, the Dacian fortress of Blidaru had strong stone walls and rectangular towers. The fortress had two main stages of construction. The eastern precinct was first built, shaped like an irregular trapeze with four rectangular towers. The gate opened through the south-west tower. At the same stage, most probably during the second half of the Ist century BC or at the very end of the Ist century BC, two towers were constructed, on inside the fortification and an other one on the outskirts. During the second stage, in the Ist century AD, the fortress was enlarged, including the isolated external tower. The fortress was destroyed during the second Trajan war, in the years 105-106 AD. The technique chosen for the construction of the walls is of Hellenistic inspiration, a technique adapted by the Dacians to their own needs and requirements,Imageobtaining an original result. Thus, the wall constructed following this technique was called in the dedicated literature murus dacicus. Such a wall had 3 m in width and its height was probably reaching 5 m. For the fortress of Blidaru murus dacicus was used for the construction of the trapezoidal enclosure as well as for the six towers. The walls were built with the participation of some Greek masons, on some of the blocks being incised Greek letters such as Θ and Ɔ. These letters as well as others are incised on stone blocks in almost all the Dacian fortresses of the Orăştie Mountains, being considered masonry signs marking the specific location of a stone block in a certain part of the wall.
The 6 four-sided towers included in the fortification wall had military purposes but the inside tower probably functioned as a chieftain residence as well. Besides the habitation-tower inside the fortress were also built wooden barracks as well as rectangular rooms were built against the inner side of the main rampart (on its north-west and south-west sides). These probably were storage rooms, and their platforms could also support war machines.
A special attention was paid to the main entrance of the fortress, the most vulnerable spot of any citadel. The ancient access, and also the nowadays hiking path ends in the same place – coming either from the uplands (the Luncani-Târsa plateau) or from the valley. One of the two gates is reinforced by a tower (in a so called à chicane system), and the other build along with the second precinct of the fortress, is flanked inside the citadel by two small walls, probably also for defensive reasons.
Stone parts of some rectangular temples of the type of the column alignments were found relatively far from the fortified enclosure, at Pietroasa lui Solomon (a private property at the south of the fortress).
Civilian constructions/ facilities
Due to its perched and isolated position, some difficulties occurred in solving the problem of the water supply. On the hill’s slope, on a level that is just slightly lower that the north-western tower, a stone rectangular vaulted water-tank , was built: its capacity is almost 200 m3. This strange position of a reservoir, outside the ramparts, was determined by the location of the spring, transported to the cistern through terra-cotta pipes. In order to properly waterproofing it, the walls of the tank were covered with a thick plaster made of lime, sand and crushed brick, elements suggesting the use of a Roman technique(opus signinum). The vault was made of limestone blocks. Also on the Blidaru Hill, in a different spot, an exceptionally preserved water tank was discovered: it was excavated in the bedrock, and doubled with wooden planks.
Terra-cotta pipe fragments were also found on several terraces near the citadel, indicating that the water supply system was, at least, a few dozens meters long.