It has always been a mystery why bluestones, the smaller stones that form part of the circle, were transported around 155 miles from Preseli Hills in Wales to Wiltshire in southern England.

长期以来，人们一直很困惑，为什么巨石阵里的一种蓝色小石头是从155英里以外的威尔士普利斯里山运到英格兰南部威尔特郡这里的。

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Over the last six years, the professors have concentrated their research on Carn Menyn - a lonely and atmospheric spot in Pembrokeshire's Preseli hills.

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They believe that the bluestones, which were transported 250km (150 miles) from the Preseli Hills in Wales to the Salisbury Plain in Wiltshire, were brought to the site because the ancient people believed they had healing properties.

BBC: 'Breakthrough' at Stonehenge dig