Origin of Stonehenge's giant upright stones revealed

New research has revealed the origin of Stonehenge's giant upright stones.

Scientists had long been confident the smaller horizontal stones came from west Wales, but it's been a mystery as to where the vertical stones came from - until now.

The origin of the nearly 5000-year-old monument's 52 vertical stones have now been solved, with researchers discovering the sarsen stones had come from 24 kilometres away in West Woods, Wiltshire, the BBC reports.

It comes after former engineer Robert Phillips, 89, last year gave back part of a stone rod made from sarsen that he had received in 1958. The rod allowed for chemical tests to be carried out, allowing researchers to pinpoint its exact origin.