Stonehenge has been extensively studied for centuries. Yet even today, we are still discovering new things about the famous site.
A ''biopsy'' of the surrounding landscape has revealed a hidden network of large pits quintled around the stone structure.
The first comprehensive electromagnetic induction study in the region, which has helped archaeologists discover hundreds of large pits, each over 2.4 meters (7.8 ft) wide. Some of these were most certainly made by human hands thousands of years ago.
The purpose of these large pits is unknown, but despite the lack of "utilitarian functions" associated with the holes, researchers believe they were linked to Stonehenge''s "long-term ceremonial structure."
Other ancient pits, discovered near the car park of the old Stonehenge visitor center, date to around 8000 BC and are associated with totem poles, props for hunting aurochs (a type of extinct cattle), and lunar observation.
Stonehenge itself was only built 5,000 years ago.
"It''s been accomplished by combining new geophysical survey techniques with coring and pin point excavation," says archaeologist Nick Snashall, who works for the Stonehenge & Avebury World Heritage Site.
"The discovery of the largest known Early Mesolithic pit in northwest Europe shows that this was a special location for hunter-gatherer communities thousands of years before the first stones were erected."
Prehistoric pit deposits are common archaeological structures in the United Kingdom and northwest Europe, but they are usually no longer wide or deeper than a meter. However, around Stonehenge and the nearby Durrington Walls Henge, they appear to be unusually concentrated.
Geophysical sensors and an archaeological investigation have discovered 415 large pits over a 2.5 km2 area. The six pits were discovered to be human-made a long time ago, two were natural events, and one was a recent agricultural deposit.
The sheer potential of these structures represents a form of prehistoric activity that was previously not seen at Stonehenge or in northwest European cities.
The round pits range in date from the Early Mesolithic, circa 8000 BC, to the Middle Bronze Age, circa 1300 BCE, and they are mostly concentrated on higher ground to the east and west of Stonehenge.
The pit''s oldest and largest is more than three meters wide and 1.85 meters deep.
The largest crack found near Stonehenge has morphed into chalk bedrock. (The University of Birmingham)
"What we''re seeing isn''t a memory of one moment in time. The traces we''ve seen in our data are divided into millennia, according to historians.
"From early Holocene hunter-gatherers to later Bronze Age inhabitants of farms and field systems, the archaeology we''re detecting is the result of a difficult and ever-changing occupation of the landscape."
The possibility for sensors to take a landscape and uncover potential archaeological sites is allowing us to get an unprecedented view of prehistoric landscapes.
Stonehenge is just the beginning.
The study has been published in the Journal of Archaeological Science.