The Drususstein (Drusus stone) is a nearly 20 metres high masonry block of Roman origin on the grounds of the citadel of Mainz. It was originally cast in marble. Researchers now largely accept that this is the structural remnant of the cenotaph mentioned by writers like Eutropius and Suetonius, erected in 9 BC by Roman troops in honour of the deceased general Drusus, in Mogontiacum (now Mainz) as part of the roman funerary art.
During the early days of the Principate the Drususstein was the starting point for elaborate memorial services in honour of Drusus, and the centre of the imperial cult in Mogontiacum. A procession road linked it to the public theater of Mogontiacum that had about 12,000 seats, making it the largest known theater north of the Alps. It may have hosted a part of the annual ceremonies at the day of Drusus' death, and probably also at his birthday.
After being robbed of its marble casing in the early Middle Ages, the Drususstein served as a watchtower in the fortifications of the city in the 16th century. For that purpose a staircase and doorframe were made in the structure, which had been up to that point a massive building. Besides the pillars of aqueducts and the stage of the theatre, the Drususstein is one of the few remaining visible reminders of Roman Mogontiacum. Together with the Igel Column, it is the only funerary monument north of the Alps dating from antiquity that remains in its original location.References:
The Amphitheatre of the Three Gauls was part of the federal sanctuary of the three Gauls dedicated to the cult of Rome and Augustus celebrated by the 60 Gallic tribes when they gathered at Lugdunum (Lyon). The amphitheatre was built at the foot of the La Croix-Rousse hill at what was then the confluence of the Rhône and Saône.
Excavations have revealed a basement of three elliptical walls linked by cross-walls and a channel surrounding the oval central arena. The arena was slightly sloped, with the building"s south part supported by a now-vanished vault. The arena"s dimensions are 67,6m by 42m. This phase of the amphitheatre housed games which accompanied the imperial cult, with its low capacity (1,800 seats) being enough for delegations from the 60 Gallic tribes.
The amphitheatre was expanded at the start of the 2nd century. Two galleries were added around the old amphitheatre, raising its width from 25 metres to 105 metres and its capacity to about 20,000 seats. In so doing it made it a building open to the whole population of Lugdunum and its environs.