It is elliptical in plan and is 189 meters ( 615 ft \ / 640 Roman feet ) long , and 156 meters ( 510 ft \ / 528 Roman feet ) wide , with a base area of 6 acres ( 24,000 m2 ) .
It is oval shaped , 189 meters ( 615 ft \ / 640 Roman feet ) long , and 156 meters ( 510 ft \ / 528 Roman feet ) wide .