6 km north of the Grobnik Field (Grobničko polje), near Studena and Klana, a nearly 5,000 m long barrier wall is preserved. Together with the Rječina River canyon and the section of the walls in Rijeka, it represents a 20 km long uninterrupted barrier line.
The beginning of the barrier is above the source of the Rječina River. From here, it extends over a precipitous canyon towards the north and turns to the northeast on the Vranjeno Hill near the Za Presiku Valley. From there, it continues to the Gorski Kotar Highlands, where it combines perfectly with natural precipitous walls and forms a strong obstacle. The barrier wall ends on a steep slope under Štulec at an altitude of 1,000 m above sea level. Because the course of the wall is partially of a horseshoe shape, the view of the inner part of the barrier is good.
The Studena barrier has four reliably proven towers, one of which is a corner tower. In 2015, archaeologists excavated a tower at the location of Mlake. They established that it was passable, but only for pedestrians. Research shows that another tower stood beside it and between the two towers, there might have been a passage for carts. We can also conclude that a Roman road from Rijeka to Trieste or Aquileia crossed this area. The other towers are located on the inner (western) side of the wall, while at the northernmost tower, the barrier changes its direction and perpendicularly breaks, so that the wall touches the opposing corners of the tower.
The area of the hinterland of Tarsatica was very important from the control point of view. From the Studena barrier, it is also possible to see the peaks on the Grobnik Field and the section of the barrier wall on the Saint Catherine’s Hill (Sveta Katarina) above Tarsatica. Towards the east and the south, the peaks of Gorski Kotar are visible and the view opens even towards Velebit. Towards the west, one can see Klana and a lower Karst plateau, which stretches past the fortlet of Gradina above Pasjak. The peaks in Istria are also visible.
