The Miami Circle

The Miami Circle in the district of Brickell, Miami, Florida.
The Miami Circle in Brickell, Florida. 

Under this layer of limestone lays a perfect circle carved between 1,700-2,000 years ago. 38-foot wide with 24 holes. Who built this? It's said that the Tequesta Native Americans. Maybe I'm facing the oldest permanent structure in the East Coast. Hidden gem in a small park by the downtown. .