A dwelling and a network of underground passageways has been unearthed by those involved in a road-building scheme.
The find was made during archeological digs ahead of the A26 project in Co Antrim, and the tunnels could be nearly one-and-a-half millennia old.
The £65m roads project involves creating seven kilometres of dual carriageway between Glarryford and the Drones Road.
The network of passages which have been found – known as a souterrain – date back to the early medieval period, ranging from 600AD to 1200AD.
Some of them are lined with stone, and were used by residents to hide from raiding parties, who would have scoured the area looking for potential slaves.
Transport minister Danny Kennedy visited the site yesterday to examine the finds and said: “The archaeological investigation works completed on the A26 dualling have been a significant success.
“Advanced site clearance works have allowed the department to carry out archaeological investigations along the scheme prior to contract award”.
He said staff from his Department for Regional Development, alongside those of the NI Environment Agency and building firm Arup, had come across a number of important finds during their archeological explorations around the scheme.
Environment minister Mark H Durkan said: “The heritage remains uncovered during the archaeological digs range from a house lived in by our earliest ancestors right up to a flax dam which the archaeologists believe was used in living memory.
“The early house dates to the Mesolithic period around about 7,000 years ago and is a particularly exciting discovery...
“This is an excellent example of how we can work together to aid economic prosperity while respecting environmental requirements and preserving our heritage for both present and future generations.”
It is anticipated that construction of the dual carriageway will begin in the later part of this year.
The improvements on the A26, which links Ballymena to Coleraine, are being carried out in a bid to reduce journey times and cut accidents.
Roads enthusiast Dr Wesley Johnston said that the area covered by the roads scheme is statistically much more dangerous than average.
One of the problems is the prevalence of tractors on the road – something which encourages overtaking manoeuvres.