Great Colonnade at Apamea overhauled drainage system. Justinian's changes included erecting a monumental "tetrastylon" made up of four high columns with a meter-high capitals. The city, was however, later sacked by the Sasanians under Adarmahan. Great Colonnade at Apamea The Great Colonnade at Apamea was the main colonnaded avenue of the ancient city of Apamea in the Orontes River valley in northwestern Syria. It was built in the second century CE after Apamea's devastation in the 115 earthquake. The avenue, which runs for nearly , made up the city's north-south axis, or the "cardo maximus". The monumental colonnade is among the longest and most
Great Colonnade at Palmyra was later added to the eastern colonnade between the Bel and Nebu temples. The middle colonnade, stretching from east to west, was constructed to connect the two earlier colonnades. Work on the central avenue began from the Monumental Arch, where it met the eastern colonnade, sometime in the early third-century CE. The section stretched until the Great Tetrapylon where it met the western colonnade in an oval plaza. The central colonnade also incorporated the portico of the baths. The central section of the Great Colonnade became the most important with several civic buildings clustered around it, including the caesareum, the