Ancient City of Goor also Gour or Gur is located 100km south of shiraz, Fars Province, next to city of Firooz Abad.
This city is believed to be founded during Achaemenid dynasty. It was encircled by Alexander, but because of its robust fortification and dedicated defenders he couldn't be able to surrender the city; then ordered to submerge the city by diverting nearby river to low area of city turn it into a lake.
After some centuries, Ardashir Babakan, the founder of Sassanid dynasty, ordered to dig a channel and discharged the lake, then rebuilt the city as his capital.
During Arabs' invasion, the city again destroyed and after passing about 3 centuries, a new city which is now called Firooz Abad, was built just next to ruins of the original city by Daylamiain Dynasty.
Goor City was in circular shape with diameter of 2km, surrounded by thick fortification and 50m wide ditch. In central area, a zone with 900m diameter divided with another wall, was served as governmental area and most of the excavated remnants of the city belong to this area.
Reference:
https://www.flickr.com