More that four thousand years ago a small ring of stones stood for around two hundred years.
Then came a single ring of huge standing stones into which a ring of smaller stones was inserted. Then another outer circle of small stones was added, before the circle of massive stones enclosed the whole thing.
This was the final phase of construction, Stonehenge’s heyday would last around 200 years until 1900 BC. The stones alignments mean that on the summer solstice the sun rises directly behind the main entrance to the monument, that is why thousands of people gather here at this time to watch the sunrise.
Take it further
Timewatch's John Farren chairs a debate on the programme's findings