STONEHENGE, one of the most visited historical sites in Britain, is universally admired as an amazing feat of engineering.

Yet to this day it remains a mystery.

Experts have traced its origins to the once great civilisations of the Stone and Bronze Ages, between 5,000 and 3,000 years ago. But what it was built for remains a riddle to this day.

If you have always had your own ideas as to what its purpose was but were unwilling to voice them for fear of ridicule, now is your chance for you to write in with your own explanations.

The Daily Echo has teamed up with English Heritage for a competition to see what people think Stonehenge was built for.

As prizes, English Heritage is offering free family passes for 20 readers who come up with the most innovative and unusual suggestions.

The earliest mention of Stonehenge was made in 1135 by chronicler Geoffrey of Monmouth, who believed that a group of giants brought over the stones from Africa to Ireland, and they were then flown across the sea to their current site by the wizard Merlin.

In that case, it would make sense that the circle of huge stones in Stonehenge were used as a giant's skittle alley!

Other outlandish theories include the 17th-century architect Inigo Jones' assertion that Stonehenge was a Roman temple.

This was particularly interesting as Jones is widely respected as the first significant English architect responsible for the revival of classical architecture.

Jones at the time, was the Surveyor-General of Royal Buildings to James I and had been given the task by the king to investigate the origin of Stonehenge.

These radical ideas are not just restricted to several centuries ago.

Only 40 years ago Gerald Hawkins, an American astronomer, used a modern computer to support his claims that Stonehenge was an ancient computer.

His book Stonehenge Decoded (1966) illustrates how a large number of astronomical alignments, prediction and measuring devices associated with the Sun and Moon can be found among Stonehenge's megalithic stones and holes.

The 20 family passes to Stonehenge that English Heritage is giving away as prizes will each admit two adults and up to three children for a visit.

And each is also accompanied by a family pass to nearby Old Sarum Castle (Salisbury), which was built in the Iron Age and later occupied by the Romans, Saxons and Normans.

It was here that William the Conqueror paid off his army and summoned all the landowners to swear an oath of loyalty to him during the 11th century.

To be in with a chance of winning one of the family passes just write in with your own explanation to the following question: What do you think Stonehenge was originally used for in 3000 BC?

The winners will be what the judges consider the 20 most unusual or original answers.

The decision of the judges is final and usual Daily Echo rules apply.

Send your suggestions, to arrive by July 31, to Stonehenge Competition, Promotions Department, Daily Echo, Richmond Hill, Bournemouth. BH2 6HH.

Terms and conditions

  • The passes will be valid only during normal opening hours: Stonehenge: 9.30am-4pm daily until March 31, 2008. (closed Dec 24 and 25 Dec).

Old Sarum: 11am-3pm daily until March 31, 2008 (closed Dec 24 and 25 and Jan 1).

  • The passes are not transferable and there will be no cash alternative to the prize.
  • Photocopies of passes will not be accepted.
  • All rights of admission reserved by English Heritage.