Miami Circle, on Brickell Point, is believed to be the site of one of the oldest known permanent structures in the United States. The site, where the Miami River meets Biscayne Bay, is a ring of holes cut into limestone bedrock. Archaeologists believe the Tequesta Indians used the holes to support posts for a structure built as many as 2,000 years ago. The site sparked a seminal fight over development and historical preservation in Miami, and is now listed on the National Register of Historic Places.