Stonehenge Avenue is an ancient avenue

Avenue (archaeology)

British Archaeologists refine the general archaeological use of avenue to denote a long, parallel-sided strip of land, measuring up to about 30m in width, open at either end and with edges marked by stone or timber alignments and/or a low earth bank and ditch...

 marked as a UNESCO

UNESCO

The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...

 World Heritage Site

World Heritage Site

A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...

. Discovered in the 18th century, it measures nearly 3 kilometers, connecting Stonehenge

Stonehenge

Stonehenge is a prehistoric monument located in the English county of Wiltshire, about west of Amesbury and north of Salisbury. One of the most famous sites in the world, Stonehenge is composed of a circular setting of large standing stones set within earthworks...

 with the River Avon. It was built during the Stonehenge 3 period of 2600 to 1700 BCE.

The avenue is aligned with the sunrise of the summer solstice

Summer solstice

The summer solstice occurs exactly when the axial tilt of a planet's semi-axis in a given hemisphere is most inclined towards the star that it orbits. Earth's maximum axial tilt to our star, the Sun, during a solstice is 23° 26'. Though the summer solstice is an instant in time, the term is also...

,, suggesting a time of most frequent use.

At the end of the Avenue, a similar ring of bluestone

Bluestone

Bluestone is a cultural or commercial name for a number of dimension or building stone varieties, including:*a feldspathic sandstone in the U.S. and Canada;*limestone in the Shenandoah Valley in the U.S...

s, Bluestonehenge

Bluestonehenge

"Bluestonehenge" or "Bluehenge" is a prehistoric henge and stone circle monument that was discovered by the Stonehenge Riverside Project about south-east of Stonehenge in Wiltshire, England...

, was discovered in 2009.