Cahokia Mounds is the largest pre-Columbian settlement north of Mexico. It was occupied primarily during the Mississippian period (800–1400), when it covered nearly 1,600 ha and included some 120 mounds. It is a striking example of a complex chiefdom society, with many satellite mound centres and numerous outlying hamlets and villages. This agricultural society may have had a population of 10–20,000 at its peak between 1050 and 1150. Primary features at the site include Monks Mound, the largest prehistoric earthwork in the Americas, covering over 5 ha and standing 30 m high.
Cahokia Mounds State Historic Site includes 51 platform, ridgetop, and conical mounds; residential, public, and specialized activity areas; and a section of reconstructed palisade, all of which together defined the limits and internal symmetry of the settlement. Dominating the community was Monks Mound, the largest prehistoric earthen structure in the New World. Constructed in fourteen stages, it covers six hectares and rises in four terraces to a height of 30 meters. The mounds served variously as construction foundations for public buildings and as funerary tumuli. There was also an astronomical observatory, consisting of a circle of wooden posts. Extensive professional excavations have produced evidence of construction methods and the social activities of which the structures are further testimony.
Cahokia Mounds is a National Historic Landmark and a designated site for state protection. It is also one of only 23 UNESCO World Heritage Sites within the United States.
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.