The Avenue dates from between 2600 and 2200BC, shortly after the construction of the sarsen stone settings.
Theories about its purpose vary. The final section, on the approach to Stonehenge is aligned on the midsummer sunrise. Was it a ceremonial processional way to Stonehenge? Other researchers think that it was the route used to transport the bluestones of Stonehenge from the river to their final destination.
A ceremonial route
A low bank defines the 'route' of the Avenue with outer ditches on both sides.
Much of the monument can only be clearly seen from the air as ploughing has reduced the height of the features. Near Stonehenge, however, the bank and ditch are still visible on the ground.
Unlike the stone-lined avenues at Avebury, no evidence has been found that stones or posts marked the Avenue's length.
The Heel Stone
The Avenue formalises the earlier north-eastern entrance into Stonehenge.
Outside the ditch, the Heel Stone stands near the middle of the Avenue, just before it enters Stonehenge. When viewed from the centre of the stone circle, it shows the direction of the midsummer sunrise. Excavations in 1979 suggest that the Heel Stone may have been one of a pair, or perhaps that the Heel Stone was moved in the past.
Immediately within the bank, the entrance was marked by three standing stones, one of which remains lying on the ground (now known as the Slaughter Stone).