Thessaloniki wears its history in layers: a Roman emperor's arch and mausoleum, Byzantine churches that spent centuries as mosques, and memorials to the 20th century. This guide covers five places that tell that story: the Arch of Galerius, the Rotunda, the church of Hagia Sophia, the Thessaloniki History Centre and the National Resistance Monument. All five are stops on our Thessaloniki scavenger hunt, which starts at the arch.
Arch of Galerius (Kamara)
Locals simply call it the Kamara, the arch. It was built in 298–299 AD and dedicated in 303 to celebrate the victory of the Roman emperor Galerius over the Sasanian Persians of King Narses, including the capture of their capital, Ctesiphon, in 298. The Via Egnatia, the great Roman road across the Balkans, ran through it, and a road linked the arch with two other buildings of the emperor's complex: the Rotunda to the north and his palace to the south-west.
What you see today is only part of the monument. Of the original eight pillars, just three on the north-western side survive, and the whole eastern half is gone. The two pillars on either side of the central passage still carry their marble panels, carved in four bands with scenes of the campaign and the triumph. Together with the Rotunda and Hagia Sophia, the arch has been a UNESCO World Heritage Site since 1988, as part of the Early Christian and Byzantine monuments of Thessaloniki.
- The relief panels on the two decorated pillars: look for soldiers on the march, battle scenes and the emperor in triumph.
- The arch's position on Egnatia Street, still the city's main east–west road, with the Rotunda a short way up the street to the north.
Rotunda
The Rotunda was built around 306 AD, probably as a mausoleum for Galerius, but the emperor was buried elsewhere, at Felix Romuliana in today's Serbia. It is a massive brick cylinder 24.5 metres across, with walls more than six metres thick, which has helped it survive Thessaloniki's earthquakes, under a flat brick dome that rises to about 30 metres. In the late 4th century the emperor Theodosius I had it turned into a church, and it served as a church of the Archangels for more than 1,200 years; it is also known as the church of Agios Georgios, Saint George.
In 1590 the Ottomans made it a mosque and added the minaret that still stands beside it. It returned to Orthodox use in 1912. Today it is a historic monument run by the Ministry of Culture, and the Church holds services there on a few feast days a year. The dome and vaults were once covered in mosaics; many are lost, but you can still see a wreath of evergreen leaves and panels of fruit and flowers.
- The minaret, a reminder of the building's three centuries as a mosque.
- The thickness of the walls, best seen in the deep window and door openings.
Hagia Sophia
A church has stood on this site since the 3rd century, but the present building dates from the 7th century, after an earlier one collapsed around 620, probably in an earthquake. It was built as a domed basilica and named, like its far larger namesake in Constantinople, after Holy Wisdom. When Sultan Murad II took Thessaloniki on 29 March 1430, the church became a mosque, and it was given back to Christian use in 1912.
Look up into the dome: its mosaic, from the 9th century, shows the Ascension of Christ, ringed by the twelve apostles, the Virgin and two angels, with the words 'Ye men of Galilee, why stand ye gazing up into heaven?'. In the apse, a plain gold cross from the period when religious images were banned was replaced between 787 and 797 by the image of the Virgin and Child you see today. The church was damaged by fire in 1890, restored between 1907 and 1909, and after the Great Fire of 1917 the dome mosaic was not fully restored until 1980.
- The Ascension mosaic in the dome and the ring of apostles around it.
- The Virgin and Child in the apse, the image that replaced the plain cross in the 8th century.
Thessaloniki History Centre
The Thessaloniki History Centre was founded by the city council in 1983 to collect and preserve written, printed and audio-visual material about the city and its region, and to support research into its past. Since 1995 it has been housed in a building on Hippodrome Square (Plateia Ippodromiou), given to it by Anastasios and Ioulia Billis. The square's name recalls the Roman hippodrome that stood beside Galerius's palace.
The centre looks after the municipal archive and several private archives, and its collection includes about 4,000 books, 3,000 photographs and 5,000 postcards, as well as posters and historic maps. It publishes a scholarly journal called Thessaloniki and holds exhibitions and lectures, which are the best reason for a visitor to step inside. It is one of the stops on our scavenger hunt.
National Resistance Monument
The last stop of our scavenger hunt is the National Resistance Monument, which honours those who fought the Axis occupation of Greece in the Second World War. For Thessaloniki the occupation was especially harsh: the city fell to German forces on 8 April 1941, and on 15 March 1943 the deportation of its Jewish community to Auschwitz and Bergen-Belsen began. Take a moment here to remember that history, at the end of a walk through much older layers of the city.
How to see them in one walk
Start at the Arch of Galerius on Egnatia Street, then walk up the street to the Rotunda. Come back past the arch and head west through the centre, past the Roman Forum and Aristotelous Square, to Hagia Sophia. From there turn east again for Hippodrome Square and the History Centre, between the arch and the sea. Finish along the waterfront by the White Tower and the statue of Alexander the Great, and end the walk at the National Resistance Monument, as our route does.
See Thessaloniki with World City Trail
Our Thessaloniki scavenger hunt turns the city centre into a game you play on your phone. The route links 10 stops, from the Arch of Galerius to the National Resistance Monument, and the arch, the Rotunda, Hagia Sophia and the History Centre are all stops, along with the Roman Forum, the statue of Eleftherios Venizelos, Aristotelous Square, the White Tower and the statue of Alexander the Great. At each stop you solve a puzzle and learn a story, at your own pace.
There is also a self-guided walking tour and an outdoor escape game in Thessaloniki, for people who prefer a different format.
Play the Thessaloniki scavenger hunt →
Take the self-guided walking tour of Thessaloniki →
Play the outdoor escape game in Thessaloniki →
Facts checked in October 2026.