The origin of the giant sarsen stones at Stonehenge has finally been discovered with the help of a missing piece of the site which was returned after 60 years. A test of the metre-long core was matched with a geochemical study of the standing megaliths.

When was the Stonehenge mystery solved?

In 1958, conservation work at Stonehenge resulted in a core of rock being extracted from Stone 58. The location of this core was a mystery until last year, when engineer Robert Phillips – a representative of the company that conducted the drilling work – returned it to the UK from his home in Florida.

Has Stonehenge been restored?

Most of the one million visitors who visit Stonehenge on Salisbury Plain every year believe they are looking at untouched 4,000-year-old remains. But virtually every stone was re-erected, straightened or embedded in concrete between 1901 and 1964, says a British doctoral student.