The earliest known smiley face may lie under Stonehenge, according to a high tech survey of the enigmatic circle of giant stones and its surroundings.
The unusual feature emerged as archaeologists from Birmingham and Bradford universities and from the Ludwig Boltzmann Institute in Vienna scanned over a 7.4-square-mile area around Stonehenge.
Photos: Stonehenge Made to Glisten
The four-year project, which is the largest geophysical survey ever undertaken, used advanced geophysical technologies such as powerful ground-penetrating radar, which can detect buried features to a depth of up to 13 feet.
The survey was able to reveal in minute details 17 unknown henge-like religious monuments, some 20 enigmatic pits which appear to form astronomic alignments, and hundred of archaeological features around the Wiltshire monument.
The smiley-face-like feature dates to about the same period when Stonehenge achieved its iconic shape, between 3,000 and 2,500 B.C. It's among some new types of monument never seen before at Stonehenge.
According to archaeologists, the Stonehenge smiley is a prehistoric ring ditch with internal or earlier features.
"The area around Stonehenge is teeming with previously unseen archaeology," project leader Vincent Gaffney, chair in Landscape Archaeology and Geomatics at the University of Birmingham, said.
Understanding Stonehenge: Two Explanations
The new findings show the enigmatic stone circle wasn't standing in splendid isolation on the edge of Salisbury Plain. On the contrary, it was the center of a rich ceremonial landscape that expanded over time.
"You've got Stonehenge which is clearly a very large ritual structure which is attracting people from large parts of the country. But around it people are creating their own shrines and temples. We can see the whole landscape is being used in very complex ways," Gaffney was reported as saying at the British Science Festival.
In some cases, such as with the Stonehenge smiley, the magnetic data images revealed patterns of circles, spirals and lines. The images basically showed ancient ditches and post holes, all relatively small monuments between 32 and 65 ft across.
But the high tech survey also revealed much larger features. One of the most significant findings was made a short distance from Stonehenge at the Durrington Walls "superhenge," the largest ritual monument of its type with a circumference of 0.93 miles.
The survey showed this "superhenge" was originally flanked with a row of massive posts or stones, perhaps up to 10 feet high and up to 60 in number.
"Some may still survive beneath the massive banks surrounding the monument," the archaeologists said.
Stonehenge Was Once A Complete Circle
One of the most intriguing feature to emerge from the geophysical survey was a 108-foot-long burial mound.
Dating to before Stonehenge, it contained a massive wooden building which was probably a house of the dead. The site housed bizarre burial rituals which included exposure of the dead bodies and defleshing on a large court.
"New monuments have been revealed, as well as new types of monument that have previously never been seen by archaeologists. All of this information has been placed within a single digital map, which will guide how Stonehenge and its landscape are studied in the future," Gaffney said.
"Stonehenge may never be the same again," he concluded.