A set of muddy Roman ruins recently unearthed near a new UNESCO World Heritage site in the Netherlands is to be destroyed by reconstruction work on a dike, archaeologists say.
The 2,000-year-old canal and highway discovered in July near the eastern city of Nijmegen surprised experts who were expecting to find only minor ruins during a routine dig ahead of work on the dike.
While a far cry from the famed bridges and amphitheatres found elsewhere in Europe, the Dutch ruins are just as important for understanding life on the far northern border of the Roman Empire along the River Rhine.
"The problem with Dutch archaeology is that we don't have large stone buildings, we don't have a beautiful Pont du Gard... We just have mud," project leader Eric Norde told AFP, referring to a Roman aqueduct in southern France.
But he added: "This is quite a great find.
"It is the first time we find a main Roman road which leads from the Roman city of Nijmegen to the western part of the Netherlands and to the northern border of the Roman empire."
The canal -- more than 10 metres (35 feet) wide -- and the road are near the major Roman-era settlement with permanent military bases in Nijmegen that were awarded the UNESCO status in July.
The "Limes" or outer border of the Roman empire that passes through present-day Germany and the Netherlands "is already part of the UNESCO World Heritage, and this main road is part of it," Norde said.
The archaeologists struck lucky during a routine excavation before work to bulk up a dike, one of the huge earthworks that make up the low-lying Netherlands' network of flood defences.
Dutch laws brought in around 20 years ago make such studies obligatory to protect the invisible heritage below the ground.
"When we started, we thought we would find a regular Roman settlement. Instead of that, we found a main canal, which leads from the river Waal to the river Rhine. So that's a great infrastructure," said Norde of RAAP, the country's largest consultancy for archaeology and cultural history.
Lots still to discover
The wide road, of which the original gravel coating has been preserved, "allows us to learn more about the road network from around 2,000 years ago," Norde said.
The canal probably linked the city to the river and was used to transport soldiers, supplies and construction materials.
But the team now only have limited time to work on the "unique" find as it will soon be covered up by the work on the dike.
Work is going ahead as planned on the dike, located in part of the Netherlands that was hit by floods in July that also badly affected Germany and Belgium.
"All the elements will get lost," Norde says.
Despite their importance, the Roman ruins were found after the designation of the UNESCO site and therefore do not officially form part of the heritage area, he noted.
Had they been discovered before then, they would have formed part of the UNESCO region, he added.
But the archaeologist was stoical about the fate of the recently discovered parts, saying it was lucky that they had found them at all, and that only a relatively small area would be covered up.
"The rest of the canal is safely 1.5 metres below the ground," he said.
"Fortunately, the road must have been about 60 kilometres long. And the Roman canal must have been about 20 kilometres long. So we have lots and lots to discover in the future!"
© Agence France-Presse