The underground world of Thessaloniki, a city founded in 315 BC by King Cassander of Macedon and named after Alexander the Great’s sister, Thessalonica, has been brought to light. The construction site that led to the city's first metro was also the city's greatest archeological dig, with three Italian businesses working on it: Webuild, Hitachi, and ATM. In the heart of a complex and articulated urban fabric, which has witnessed over two thousand years of history, a technological subway has been in operation since last Saturday, the day of the inauguration. The subway consists of a 10-kilometer-long line with 13 stations, which serves some of the most populous and central districts of the city. The trains are driverless and equipped with high-tech automation systems. The new subway route, which was constructed by Webuild in collaboration with Hitachi and the Greek Aktor, will be traversed by thousands of individuals. The Milanese-ATM Transport Company, in consortium with Egis, is responsible for its management. Passengers will be able to appreciate the exceptional features of this project as they travel through time, passing through the eras of the Romans, the Byzantines, and the Ottomans. They will also be able to explore the remnants of the Ancient Greek sewage systems and the forgotten basilicas of Christian influence.