Saudi Arabia has opened to tourism an ancient archaeological treasure to which entry has been strictly limited for almost a century for religious reasons, and which is very similar to the nearby ruins of Petra, Jordan.

The construction of Madain Saleh - "the cities of Saleh" - was started 5,000 years ago not far from the city of Tabuk.

Access to the area has been largely banned since the Al Saud dynasty took control of the country in 1932, in strict obedience to an order of the prophet Mohammed not to enter that city except weeping and fasting, because of the tragic fate of the people who had lived there.

The area was inhabited by Tamudians, ancestors of the Arabs, who possessed an advanced culture that included skill at carving inscriptions in stone as well as building houses and palaces in the mountains.

The Koran says that God sent his prophet Saleh to the Tamudians in order to stop them from worshipping idols.

When the skeptical Tamudians asked Saleh to show them that he really was God's messenger, the prophet turned a rock into a huge camel able to give enough milk for the whole tribe.

But the recalcitrant Tamudians decided to kill the camel to free themselves of Saleh.

The divine response was to exterminate the tribe, while Saleh and a few believers hurried away.

At the end of December, the Saudi General Organization for Tourism and Archaeology announced it would open the area to the public and was prepared to accept tourists.

In 2008, UNESCO designated Madain Saleh as a World Heritage Site, the first in Saudi Arabia.