The Rotunda is one of the most imposing monuments of Thessaloniki and one of the most important of the Roman period in Europe. With its architectural power and the unrivaled art internal mural mosaics, constitutes a special monument, unique balancing between the pagan and the Christian world. It was founded in the early 4th AD century, probably as a temple of the ancient worship or mausoleum of Constantine (306-337) located on the axis of the processional route, which connected the triumphal arch of Galerius with the palace complex, near the present Navarinou Square. The circular and dome roofed emblematic monument has a height of 29.80 m., diameter 24.50 m., width of walls 6.30 m.. Architectural can only be compared to the Pantheon in Rome. Shortly after its construction, it was converted into a Christian church dedicated to the Aghioi Asomatoi or the Archangels. It was Metropolis of Thessaloniki from 1524 to 1591, when it was converted into a mosque by the Ottoman conquerors until the liberation of Thessaloniki in 1912. The dedication of the monument to Saint George is due to the neighboring, small, homonymous church. Today the Rotunda, with history of more than 1700 years, is at once church and cultural – archaeological monument, in which the tourist visiting, the ecclesiastical liturgy and hosting cultural events are all combined, matching the monument’s character and history.