The mystery beckons. Clues appear then contradict each other and often themselves. Somewhere beneath the sands of Saudi Arabia's Eastern Province lie the remains of the fabled city of Gerrha. For Rami Kamal, determining their location has been both a dream and source of intellectual stimulation for several years. As he explained to members at a recent meeting of the Arabian Natural History Association, "The whereabouts of Gerrha is one of the most important unanswered questions on the Arabian Peninsula."

Gerrha (Al Jarha? in Arabic) was strategically situated on the trade routes passing north from what is now Oman and through Yabrin. Well supplied with water and food, the city became a natural magnet for caravans laden with frankincense and myrrh form Oman, spices from India and silk from China. From Gerrha these luxury goods of the ancient world would be transshipped by sea through the Arabian Gulf or follow land routes to Mesopotamia and Asia Minor through modern-day Iraq or cross north through Al Jawf to Petra, Gaza and beyond.

By the late third century BC, Gerrha was the principal commercial center in the Gulf. Its inhabitants grew fabulously wealthy from the duty (typically forty percent) imposed on the goods passing through its streets. The desert and the vast sand sea that surrounded it on all sides provided a natural barrier that no conqueror could breach despite the temptation of the city's vast wealth.

The Greek geographer Strabo called it the "white-walled city" and wrote that "the people [of Gerrha] live in houses made of salt, and the people frequently sprinkle the houses and thus keep the walls firm." Classical writers Polybius and Pliny the Elder also wrote of Gerrha's affluence and her hegemony over the region. But fame and fortune were fleeting. By the third century, commerce had fallen as the Roman and Parthians warred and internal dissension wracked the Empire. The Romans also re-routed all trade through Palmyra, severely undermining a number of old trade centers, including Petra and Gerrha. In the face of economic collapse, Gerrha was abandoned. Its location was forgotten. Its name became the stuff of legend.

"The search for Gerrha is complicated," said Kamal, "because none of the classical authorities can agree on where it was." Strabo, writing in 25 BC, places it 50 miles from the sea. Pliny, a hundred years later, states that Gerrha was 50 miles from Al Hasa and 50 miles from Bahrain. The British historian Edward Gibbon equates Gerrha with Qatif. Other candidates include Gerrayah, Al Hasa and Qariyat Al-Fau.

Kamal has focused his attention and efforts in nondestructive exploring on an area at the eastern end of Half Moon Bay. There he believes he has found the remnant of an ancient breakwater in an area that may have served as Gerrha's port. Further inland, fellow explorer Robert Gex, introduced him to an area of ancient ruins not far from the mouth of an old riverbed and past old salt deposits. Kamal points out that the locales he is presently examining are ideal for trade with a protected port, easy access to both the sea and land routes, plentiful potable water and agriculture. The nearby salt deposits may have been the quarry for the salt blocks used to build the city.

The question of whether or not Kamal's site is Gerrha will require years of archaeological investigation to answer. Still, the challenge of Gerrha has taken Kamal on a personal voyage of discovery and intellectual growth that is hard to equal and easy to envy.