In Spinal Tap’s song “Stonehenge”, they asked the same question - albeit in a lyric.
“And where are they now - the little people of Stonehenge?”
"In ancient times, hundreds of years before the dawn of history, there lived a strange race of people: the Druids. Nobody knows who they were…or…wot they were doin'. But their legacy remains, HEWN, into the living ROCK, of Stone'enge…"