Ancient people probably assembled the massive sandstone horseshoe at Stonehenge more than 4,600 years ago, while the smaller bluestones were imported from Wales later, a new study suggests. The conclusion, detailed in the December issue of the journal Antiquity, challenges earlier timelines that proposed the smaller stones were raised first.

"The sequence proposed for the site is really the wrong way around," said study co-author Timothy Darvill, an archaeologist at Bournemouth University in England. "The original idea that it starts small and gets bigger is wrong. It starts big and stays big. The new scheme puts the big stones at the center at the site as the first stage."