Fortica, the fortress in Otočac is a real rarity because it is one of the only two remaining regular triangular towers in Croatia, and there are only a few of them left in Europe. The fifteen Stations of the Cross placed on the Fortica hillside add to the city's religious significance while also offering each visitor a unique artistic experience.

The Otočac sculptural Calvary begins at the foot of the Fortress with the composition of Holy Trinity. It continues with fifteen stone stelae, which were placed from the foot of the Fortress to the chapel of the Our Lady of Sorrows, which is located almost at the very top of the hill, enriching the existing view of this area, returning to it the already somewhat forgotten memory of Calvary, as the religious regiment called this hill.

The locals of the city of Senj constructed the Fortica fortress in 1619 to protect the town of Otočac from the hill of the same name. Otoac was situated on an island in the midst of the Gacka River. Senj was able to successfully repel Ottoman raids in the Gacka region because to this strategy.

It was a fort with three towers, the largest one on the east side and two smaller ones on the west side, connected to each other by walls 1.80–2 m thick. It was built quickly with smaller stones, apparently there was neither time nor money for carving stone blocks. Inside was a very narrow yard with cisterns where water was collected. Fortica was used for the permanent residence of soldiers, as a storehouse for ammunition and gunpowder and as a storehouse for food, with kitchens and dormitories.

Archaeological research revealed the walls of each of these towers and connecting walls, and the threshold of the entrance door was also found.

The entrance to Fortica was on the south side towards Otočac. The entrance door was high above the ground, so at the time the Fortress was being built, it was only possible to get inside with a ladder, and later a porch with stairs was built. At the time of military use, the hill of Fortica was a bare hill, without trees because defense reasons dictated it. The first commander of the Fortress was Andrija Kolaković. Fortica was abandoned in the second half of the 19th century, when Otočac began to systematically develop as an urban area. The Otočac regiment's key military structures were all situated beneath the Fortica. Fortica's transformation into a powder chamber in 1804 is proof that it started to lose significance at the start of the 19th century. A powerful wind lifted and dropped the roof from the widest tower to the ground in 1882, so in addition to carelessness, time also played a role in the fortress' decline.

Fortica was reforested around the beginning of the 20th century. A Czech pine was planted on the pharmacist astek's private property up on the hill. Up to the Second World War, the new woodland was growing wonderfully.

In 1941, the Italians who came to Otočac had the trees cut down and placed their artillery barracks there.

It is interesting to mention that the Fortica fortress in its restored and preserved condition is now the only remnant of the Renaissance in the area of ​​Otočac. Namely, before the Renaissance, square towers were built, much less often triangular ones, and in the Renaissance, forts or castles were strengthened with round towers.