Archaeologists have been working against the clock to save what they could from the perfect circle, which is up to 2,000-years-old.

The frantic excavation however was granted a reprieve from the bulldozers by developer Michael Baumann, who is poised to build a $100m apartment complex comprising two twin towers and a car park.

The discovery has caused much excitement in the archaeological world and experts have until 26 February to excavate what they can.

Does the circle represent Maya carvings of sea animals?

Project supervisor T.L.Riggs, said: "It looks like Stonehenge in negative. Instead of stones - holes."

Some experts believe that holes carved in the circle, which is 38ft in diameter, were made by Tequesta Indians to serve as a celestial calendar.

The Tequestas' settlement, now the site of Miami's financial district, was wiped out by disease and war after the Spanish arrived in Florida in the early 1500s.

Tequesta evidence

"It is unique, nothing like it has been found in South Florida," said John Ricisak of the Miami-Dade County's Historic Preservation Division.

"To my knowledge, it is the foundation of a Tequesta structure of some sort, it would the first hard evidence of one that's ever been documented archaeologically."

Studies of relics found near the circle, such as shells and beads, have added weight to the celestial calendar theory, as a carving on the circle, similar to an eye, lies on an east-west axis - possibly in alignment with the equinox.

But others dispute this, as no Mayan artefact has ever been found in the US.

But the arcahologists cannot claim total victory.

Buying time

Miami-Dade Circuit judge Wilson threw out a request filed by the Dade Heritage Trust for an emergency injunction to block construction until experts made a decisive study on whether the site should be preserved.

Becky Roper Matkov, executive director of the Trust, said: "We've bought some time. I hope we can apply political pressure to force the city to take a stronger hand to save the site."