The discovery of a major prehistoric site where experts believe an open-air royal temple once stood has stalled construction of a controversial four-lane highway in Ireland.

A large circular enclosure estimated to be at least 2,000 years old was exposed at Lismullin in County Meath, by road-builders working on a 37-mile-long (60-kilometer-long) road northwest of Dublin...just 1.25 miles (2 kilometers) from the Hill of Tara, once the seat of power of Ireland's Celtic kings...

Work was halted last month after archaeologists with the National Roads Authority (NRA) reported a large timber monument 80 meters (262 feet) in diameter, with a 16-meter-round (52-foot-round) structure inside thought to have been a temple.

Artifacts unearthed at the site include a stone axe head, a pottery fragment, and an ornamental pin. An ancient buried dog was also excavated nearby.

Archaeologists say the monument probably formed part of an important ceremonial complex centred on the Hill of Tara, where remains date back to the Stone Age.

Archaeologist Joe Fenwick of the National University of Ireland, Galway, described the Hill of Tara as Ireland's equivalent of Stonehenge or Egypt's Pyramids.

"It's commonly recognized that this valley [where the new site was found] is part of Tara, which is the pre-eminent archaeological site of our nation," he said.