Given away by strange, crop circle-like formations seen from the air, a huge prehistoric ceremonial complex discovered in southern England has taken archaeologists by surprise.

A thousand years older than nearby Stonehenge, the site includes the remains of wooden temples and two massive, 6,000-year-old tombs that are among "Britain's first architecture," according to archaeologist Helen Wickstead, leader of the Damerham Archaeology Project.

For such a site to have lain hidden for so long is "completely amazing," said Wickstead, of Kingston University in London.