One of world’s most baffling mysteries became even more mysterious after new archaeological findings announced earlier this month appeared to cast a strange new light on the question of who built the ancient stone circle monument known as Stonehenge. At the same time, the new findings may answer at least one long-puzzling question about Stonhenge, while raising many more.\nThe circle of massive stone monoliths stands in an open field on Salisbury Plain, a rural area in the south of England. The stone circle is believed to have been built in stages over about a 1,500-year period starting in 3,000 B.C. For comparison, the date when Stonehenge is believed to have been completed is about 300 years before the events of the Trojan War depicted in the epic Greek poem, The Iliad. The date when construction began would have been about 1,000 years before the birth of the Biblical character Abraham.\nBut now archaeologists say that at least two of the most important stones in the enigmatic structure date from even earlier than 5,000 years ago — millions of years earlier. Archaeologists have long assumed that the massive stones that make up the monument were transported by the prehistoric builders from the Marborough Downs region about 20 miles from the site where Stonehenge stands.\nBut archaeologist Mike Pitts now says that the largest stone at the site, known as the heel stone and weighing about 120,000 pounds, was not moved at all and, in fact, has existed at the site for millions of years. If true, this discovery is especially remarkable because the heel stone aligns with the sunrise during summer.\nResearchers have long theorized that Stonehenge was constructed as a temple for a prehistoric sun-worshipping cult, which designed the layout of the rocks to align with the sunrise. But if the heel stone was in place before Stonehenge was built, its presence on the plain was likely the reason that the inhabitants of prehistoric England decided to build the monument there, archaeologists now believe.\nThe fact that the heel stone and its companion, known as Stone 16, appear not to have been carved or sculpted by human hands — unlike the other stones in the monument — also suggests that the stones existed on the Salisbury plain long before the human builders of Stonehenge migrated to the site.\nThe new discovery by Pitts appears to answer the question of why Stonehenge was built on the Salisbury Plain — but only deepens the mystery of why the stone circle was built, and by whom. Recent discoveries using 3D laser imaging and ground-piercing radar have revealed that at least 15 other, similar monuments were also built around the Stonehenge site, and dozens of ancient gravesites have also been discovered there, suggesting that the entire plain may have been some sort of sacred religious site to the inhabitants of England 5,000 years ago — inhabitants who may have been part of a society led by powerful women. Many of the most prominent graves surrounding Stonehenge belong to women.\n\nPitts discovered a massive, 20-foot-deep hole near Stonehenge. He now believes that the heel stone was excavated from that pit, perhaps centuries before the remainder of the monument was built — a possibility that only deepens the mystery of who lived at Stonehenge and who built the structure. Discoveries of the other monuments on the plain indicate that humans may have lived there as long as 10,000 years ago — making the place now known as Stonehenge the place in England where human beings have continually lived for the longest time.