Scientists find Stonehenge's larger neighbor

Large stones dating back 4,500 years measuring 15 feet long were found about 3 feet underground.

>> Read more trending stories  

Researchers said the discovery that it is on "an extraordinary scale" and unique, the BBC reported.

Experts believe that the site, which has not been excavated, to be a Neolithic ritual site that surrounded springs and a dry valley leading to the River Avon, the BBC reported.