A huge triangular stone monument uncovered in Saudi Arabia provides yet more evidence that ancient humans were building large complex structures much earlier than previously thought.

The structure, some 155 feet long, dates back to around 8,000 years ago.

It was found during an archeological dig at a site in the Dumat al-Jandal oasis, in northern Saudi Arabia.

The huge monument, like many early megalithic constructions, is thought to have been built in several stages.

The international team led by Olivia Munoz, a researcher at the CNRS, the official French National Centre for Scientific Research, dated the structure by examining objects and human remains from deposits found in and around the platform.

"Analysis of the platform and nearby tombs highlights the persistent funerary and ritual use of this area over millennia, illuminating nomadic pastoralist lifeways in prehistoric Arabia.

"Thousands of years older than Stonehenge, this mysterious platform would have been built when people in the region still lived a largely nomadic existence.

"Their organisation in the repository - disarticulated and deposited as a bundle - shows that this is a secondary deposit, i.

e.

, that the body had decomposed elsewhere, and that only certain bones were selected and placed in the platform," Munoz told Haaretz.

"The deposition of these human remains was probably of strong symbolic importance from the early days of the use of the platform, which may have been a place of commemoration at the time.

"Unlike prehistoric relics in Europe and the Near East, the megalithic monuments of Arabia still remain comparatively unexplored.

These gigantic dry-stone structures, say the researchers, still hold many secrets, such as when they were built, how they were built, and was they meant to their builders.

Munoz says that other similar sites - some of which include "kites" that are thought to be either tombs or elaborate animal traps, are dotted across the Saudi peninsula.

"However, few have been explored, and it's often difficult to date them, which is one of the novelties of our study," she says.

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