South Wiltshire is the location of the famous prehistoric stone circle of Stonehenge. The monument was built and adapted in three phases over a huge time span, between approximately 2,950BC and 1,600BC. The first Stonehenge was a circular bank and ditch, probably containing timber uprights, then during the second phase (2,900-2,400BC), new timber settings were erected in the north-east entrance and at the centre. During these early phases it seems the purpose of the monument was the observation of the movements of the moon through the entrance, and it may also have been linked with death and funerary rituals. The Stonehenge we see today was developed in the third phase (2,550-1,600BC). The Hele Stone and another stone west of it were erected outside the monument pointing towards the approximate point where the midsummer sun rose. Bluestone pillars brought from the Preseli mountains in Wales were erected around the Altar Stone, then came a horseshoe-shaped setting of large trilithons. Surrounding these were more bluestones, then a ring of sarsen stones. The Avenue was also constructed at this time, connecting Stonehenge with the River Avon and aligned on the point of sunrise of the summer solstice, emphasising the change of observation from the moon to the sun.