Kalaja

The Illyrians built the castle on a small peninsula on the right-hand side of the Pristan Gulf, an arm of the Adriatic, and their Cyclopean Wall is the oldest surviving work on the site. The complex has flourished for some twenty-five centuries and is counted among the oldest urban architectural groupings on the Adriatic. In the 6th century the town had two gates: a lower, eastern one reached from the sea, and an upper, western one reached from the land.

The walls were destroyed often in war and rebuilt as quickly by the residents to keep their fortresses and houses safe. Major changes were the work of the Byzantines, Serbs, Venetians and Ottomans, and the modern city of Ulcinj was built outside the circuit.

On the upper, highest level stands the citadel-fortress with the Tower of the Balšić (Albanian Kulla e Ballshajve), which dominates the old town and the country around it. The tower is connected with the last representatives of the Balšić dynasty, a wealthy family from the Shkodër area, then part of Zeta, who had made Ulcinj their residence by the end of the 14th and the beginning of the 15th centuries. The Ottomans later added the tower's third floor and the spherical dome on the ground floor. It is considered one of the most representative works of medieval architecture in Montenegro.

The castle is believed to have housed the Venetian administrator for Ulcinj, in the building known as the Venice Palace, and later rulers used the same building as their court. During the Ottoman occupation of the town these edifices served as the residence of the local ruler. Kulla e Ballshajve, on the southern level of the old town not far from the Venice Palace, has a square structure called Fusha Qehajes, from the Turkish çehaja, a military rank.

The small square in front of the Church-Mosque, ringed by arches, was once the town market. From the middle of the 17th century Ulcinj became a significant slave market. Most of those held in Ulcinj came from Italy and Dalmatia, seized by Ulcinj pirates who robbed the rich villas along the coasts of Apulia and Sicily. The pirates treated them as convicts and used them for no kind of work; instead they were kept as hostages while a ransom was demanded of their relatives, friends or countrymen, and the captives had to be allowed to send word home so that the ransom could be offered.

From the middle of the 18th century demand changed and the courtiers began to look for slaves from Africa. They would later be sold on again, or brought to Ulcinj, where they might soon become free citizens and work in agriculture or seafaring. A small community of their descendants still lives in Ulcinj.

Water was taken from 600 metres north-west of the fortress, near a place called Javor, where a number of reservoirs collected rainwater for the citizens of the old town to use if there was a siege. The fountain in the old town was built in 1749-50; the town's fountains were endowed as vakf by individuals, cut from stone and incised with a tarih giving the year of construction and the name of the benefactor.

The old town is today inhabited mostly by Albanians. The Balšić Tower has been given over to use as a gallery and a venue for poets' nights, and the Venice Palace and Kulla e Balshajve serve as luxury accommodation for visitors to Ulcinj. Montenegro entered the site on its tentative list for World Heritage status on 28 February 2018.