Despite the lack of a roof, the research team has found, the original circle of 157 standing stones (only 63 complete stones remain today) once acted like a sound chamber. For people in the inner sanctum 4,000 years ago, the placement of stones would have amplified and enhanced human voices and music in a way that must have been spellbinding. If you were outside the circle, though, the sounds were muffled and indistinct. This finding has added credence to the growing consensus that rituals at Stonehenge were for a small elite. The study was conceived by Trevor Cox, an acoustical engineer at the University of Salford. “Some acoustical research had already been done at Stonehenge, but it was all based on what’s there now,” Cox says. “I wanted to know how it sounded in 2200 B.C., when all the stones were in place.”