 Big Mound City is the site one of four recognized monumental Native American earthworks built in the Lake Okeechobee Basin area of southeastern Florida.Dating from the Glade III Glade Period (circa 1000 AD), it is a combination of at least nine mound structures and a ridge complex, including radiating causeways and crescent-shaped man-made ponds.Some of the mounds have been identified as burial mounds.