English Heritage inspectors have been visiting a 4,000-year-old feature in Herefordshire to see if it should be preserved as an ancient monument.
Archaeologists have said the Rotherwas Ribbon, found by road builders, could be as important as Stonehenge.
Herefordshire Council said a protective shield will be built over the site to preserve it for future generations. A relief road will then be built over it.
If inspectors schedule the monument, work on the road will have to stop.
The 197ft (60m) long ribbon of stones was discovered by diggers working on the new access road in Rotherwas, near Hereford.
It is made up of a series of deliberately fire-cracked stones and appears to have been deliberately sculptured to undulate through the whole of its length that has so far been uncovered.
Archaeologists have said there are no parallels to the site in the rest of Europe, with the closest similar artefact being the 2,000-year-old Serpent Mound of the Ohio River valley in the US, a 1,330ft (405m) long effigy of a serpent.
Dr Keith Ray, Herefordshire County Archaeologist, said the site was unique because it was built in three dimensions.
The inspectors are expected to give their verdicts in the next few weeks.