Carved into the bowels of the Janiculum hill is a huge underground car park that is being built to ease the traffic congestion around St Peter's Square during an intense year of religious celebrations. But the ambitious pounds 28m project - financed jointly by the Vatican and the Italian government - is in jeopardy because of a wall. Not any old wall, but a massive brick structure, about 20 feet high and nearly as wide, that was, 1,800 years ago, part of the home, or Domus of awell-to- do family.
Descending what is to be the entry ramp to the new car park one comes face to face with it.
The scene is reminiscent of Federico Fellini's film Roma, when workers on ametro line stumble upon anancient villa, complete with mosaics and frescoes, only to see them disintegrate on contact with the air.
On the other side of the immense wall, to one side, are several rooms with terracotta floors and well-preserved frescoes. They appear to be the servants' quarters of a patrician family home. Their discovery in August brought work on the ramp to a sudden halt.
It was the start of a complex and at times paradoxical debate over Rome's past present and future, whose tones have grown fiercer as the deadline for the car park completion draws closer.
Archaeologists have dated the house to the second century AD; most of the frescoes have now been transferred to a museum, to prevent damage but environmental and heritage groups argue the the remains must be preserved and excavation continue to uncover the rest of the house. They have staged sit-ins, lobbied parliament and appealed to Unesco.
Rome's mayor Francesco Rutelli, a former leader of the Green party, finds himselfopposing his former allies, arguing that not completing the car park would cheat taxpayers and risk chaos during such a major event.
Up to 40 million people are expected in Rome next year as the Jubilee, which was first held in 1300, coincides with the 2,000th anniversary of the birth of Jesus Christ. As the extraordinary commissioner for the Jubilee Year, Mr Rutelli boasts that 90 per cent of Jubilee projects have been completed on time and within budget and doesn't want any last minute hitches to ruin that record.
After months of buckpassing, the problem has now landed in the lap ofItaly's Cabinet which is today due to decide whether work on the ramp can proceed, destroying the ancient wall, or whether it must remain intact, allowing further archaeological excavation.
The furore over the access ramp and the Domus has distracted attention from the car park itself, which is wholly on Vatican territory and close to completion.
Lorenzo Bianchi, a respected archaeologist, has accused the Holy See of silently destroying a series of galleries and caves without telling a soul. The Vatican spokesman Joaquin Navarro Valls has said that "no archaeological remains have been found on Vatican soil".
Mr Bianchi and other academics maintain that among the tons of soil dug out to make space for the six storey parking building were the graves of early Christians martyred by Nero as scapegoats for the fire that destroyed Rome AD64.
If that were proved, the fuss over the Domus and its wall would pale into insignificance. That seems unlikely though, given that the earth removed to make way for the car park has long since been carted off and excavators and bulldozers have been in action, unchecked, for months.