In the northwestern part of the Upper Town, above Olympiados Street and close to the Byzantine walls, the Palaeologian Church of Agia Aikaterini is a great Byzantine attraction, which is included in the list of UNESCO World Heritage Sites. The cruciform church, built at the beginning of the 14th century, with a central dome and four smaller domes at the corners, is a typical building of the "Macedonian School", while the fresco is placed in 1315.

The temple was built to honor Jesus Christ. After the liberation of the city in 1912, it was dedicated to Agia Aikaterini and was named after her. In 1481 it was converted into a mosque and during this period it underwent several operations. The restoration works of 1946 revealed interesting masonry that had been covered and today many are preserved in this temple, with bright colors and rich worldwide sights on their own, along with the very characteristic architecture of the temple.