15. The Roman Forum

The Roman Forum (also known as the Ancient Agora or Roman Agora) served as the city's economic, commercial, administrative and recreational hub for about three centuries. 

Thessaloniki's Roman era began in 149 BC, after the Romans defeated the last king of Macedonia and the city became part of the Roman Empire. Thessaloniki became the capital of one of the four provinces into which the Romans divided Macedonia. As was customary in every Roman city, including newly conquered settlements, a forum was established here.

The construction of Thessaloniki's Roman Agora began in the late 2nd century AD, with a second building phase in the early 3rd century and additional expansions up to the 4th century AD. It was built on the model of the Agora of Rome and gradually acquired a monumental character.

Its location was no coincidence as it was strategically positioned at the intersection of two major roads at the time. One was the Via Egnatia (which at this point coincides with the modern Egnatia Odos motorway) and the other was a road perpendicular to the Via Egnatia, likely running through the city from the Acropolis (where the Upper Town is located today) down to the sea.

The Agora remained active throughout the 2nd, 3rd and 4th centuries AD. It was gradually abandoned as the city's political centre shifted east to the Galerius Palace Complex. 

It continued to be used to some extent during the Byzantine period, with minor modifications. Later, During the Ottoman period, the Agora area was allocated to Jews expelled from Spain, who then settled in Thessaloniki. 

The site became buried over the years until excavations in the 1960s to build the city's courthouse revealed this ancient gem and led to the courthouse being built elsewhere.

The Roman Forum (or Agora) of Thessaloniki spanned approximately 20 hectares, centred around two rectangular spaces.

One of these spaces is part of the excavated area visible today. It was paved and bordered by a two-storey Π-shaped building that enclosed three of its four sides. Arcades featured on both floors, with Corinthian columns on the ground floor and Ionic columns above. Behind the arcade, on the eastern side of the complex, there were other important buildings: a mint, an Odeon and an archive – remains of which are visible today.

On the southern side is the Krypti (or Hidden) Stoa, built below the level of the square. This arcade essentially "supported" that side of the Π-shaped structure, functioning as a basement and likely serving as storage for the shops. The Krypti Stoa is now the entrance to the Museum of the Agora, which is well worth a visit. Beyond what is visible today, excavated finds suggest that the Forum also contained baths, shops, streets and a sewage system. The entrance was from its northern wing, which runs along today's Olympou Street, where the Roman Forum Park now stands. 

The second rectangle of the Roman Forum operated as an open square without arcades. It remains unexcavated and lies below the modern Ancient Agora Square between Filippou and Egnatia Streets. At the level of Egnatia Street, there was another impressive ancient arcade, known as the Stoa of Idols, which also served as the entrance to the Forum. This arcade was decorated with reliefs of eight mythical figures. In 1864, on the orders of the Ottoman government, the sculptures from this arcade were transported to the Louvre in Paris, where they remain today.