Work has begun in Wiltshire (England) to straighten two huge prehistoric standing stones which had started to lean at a precarious angle. The twin megaliths stand near the centre of the largest prehistoric stone circle in Europe at Avebury and have developed a list of 15 degrees. The movement was revealed by comparisons of a 3D computer-generated graphic of the stones in their present state with engravings by William Stukeley, an 18th-century Lincolnshire antiquary, says The Times.
     The 16ft coffin-shaped stones each weigh an estimated 50 tonnes. The first job will be to excavate behind them to establish how deeply rooted they are and to create a gap into which each stone can be pushed. Once the stones are upright, cement will be poured in around them to prevent any further movement. The twin megaliths, known as the Cove, are within a massive circular ditch and bank earthwork 30ft deep and more than 1,400 yards in circumference. Although the two stones have stood undisturbed for at least 4,000 years, it is only in the past few decades that the tilt has developed. The National Trust, which owns the site, describes the stones as "perilously close to collapse"
     Archaeologists started also digging around the site and have been surprised to uncover what could be one of the largest standing stones in the country. Experts at English Heritage and the National Trust say the stone could weigh in at 100 tons, rivalling the largest megaliths at its fellow site in Wiltshire, Stonehenge.
The team from the Universities of Wales, Leicester and Southampton found the stone was buried much deeper beneath the ground than previously thought. They found that one of the stones, which stands 14ft (4.4m) high above ground, exists at least 7ft (2.2 m) below the surface and could possibly go down to 10ft (3m).
     Amanda Chadburn, Inspector of Ancient Monuments at English Heritage, which is the guardian of the stones, said: “We were amazed when we discovered that the stone went so much deeper than we expected. Ground penetrating radar and probing had suggested it existed to only about one-and-a-half to three feet below the surface. It is absolutely enormous and could weigh as much as the trilithon at Stonehenge.”
     Although it was originally planned to bring both stones at the Cove to an upright position the investigations show that only the other stone, which is 16ft (4.9m) high above ground and predicted to exist to 1.25m below ground, requires straightening. The monster stone will now be left, as it is considered safe. Rob Mimmack, property manager at Avebury for the National Trust, which owns the monument, said: “The stone is being fixed in the ground with lime concrete. Within two to three weeks we will be taking down the scaffolding and people will have access to the stones again for the first time since 1997 when they were fenced off for safety reasons.”
     The recovery of preserved organic material from soil samples during the excavations will enable radiocarbon dates to be taken. For the first time the Cove will be able to be dated by modern methods.

Sources: Ananova/Daily Telegraph News (8 April 2003); The Scotsman (17 April 2003), The Guardian (18 April 2003)