New Stonehenge Discovery: What Took So Long?

 First off, what is Stonehenge, anyway?
Question of the ages, right? The prehistoric monument near Amesbury, England, has long defied neat historical explanation. Scholars estimate that building started some time around 3100 B.C., and construction continued in several phases over centuries. There are plenty of theories as to what the site may have been used for and how the multi-ton stones got there. Most of these theories point to some sort of ritual use of the site, though whether it was primarily a burial site, a place of healing, or a giant celestial clock is still debated.

What new information have researchers discovered?

As part of the Stonehenge Hidden Landscape Project, a partnership between the University of Birmingham in the U.K., the Vienna-based Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology, and several other institutions, researchers found 17 ritual monuments, previously undiscovered, dating back to the same time period as Stonehenge, as well as new information about the massive prehistoric monument next door, Durrington Walls.
 

Why did it take so long to uncover these monuments?
Most of the area around Stonehenge has never been explored by researchers. Previous scholars (and early looters) excavated in and around the monument, but none had performed an in-depth survey of this much of the surrounding site.
 

How did these researchers do it?

Starting in July 2010 and spanning four years, researchers examined the site using non-invasive survey technologies, including motorized magnometers, ground-penetrating radar arrays, electromagnetic induction sensors, earth resistance surveys, and 3-D laser scanners (most of which were rigged onto the back of a quad motorcycle and dragged across fields like a bit of highly scientific farm equipment).
Using this wealth of data, the researchers mapped the site in detail, discovering new information about the prehistoric monuments. They found a 108-foot-long burial mound called a long barrow, dating back to before Stonehenge, containing evidence of a large timber building that would have been used in burial rituals. The research also uncovered a new type of prehistoric monument–pits dug into the ground that seem to align with the movement of the sun.
Furthermore, the survey also found evidence of early construction at Durrington Walls, a huge Neolithic “super henge” two miles away from Stonehenge. The new map shows that in an early stage of the monument–which has a circumference of almost a mile–it was surrounded by a row of up to 60 stones or large posts, some of which may still be buried in the banks around the monument.

Why does it matter?
“After centuries of research, the analysis of all mapped features makes it possible, for the first time, to reconstruct the development of Stonehenge and its landscape through time,” Wolfgang Neubauer, director of the Ludwig Boltzmann Institute, said in a statement. This, in turn, can give us a better idea of what the site might have been used for.
“The point I think we’re coming to,” researcher Vince Gaffney told Smithsonian magazine, “is that increasingly we can see the area around Stonehenge as providing extensive evidence for complex liturgical movement—which we can now understand, largely because we know where things are.”
With new, non-invasive technologies, archeologists have the opportunity to dig deep into ancient sites, without doing much actual digging, a win-win for human knowledge and historic preservation.