On a clear day in February 2013, the turbulent waters off the coast of Mafia Island, one of the islets in the Zanzibar archipelago, had fallen to an unusually low tide. A few nautical miles away, a strange formation poked above sea level. A helicopter whirred overhead.
For years, the “lost city” of Rhapta had baffled scholars, divers, and archaeologists. Dating to roughly 50 A.D., it was originally documented in Ptolemy’s Geography as Africa’s first metropolis—and a trading hub for tortoiseshell and metal weapons. It was one of the wealthiest cities of its time. Yet little has been added to Rhapta’s story since its disappearance more than 1,600 years ago, aside from the vague discovery that its remains were buried somewhere off the coast of Tanzania.
Now there’s reason to believe that the algae-covered formation spotted from the skies in 2013 could be the mysterious sunken city. Pushing the theory is diver Alan Sutton, who documents hidden wreck sites and blue holes online—and who spotted the ruins from the helicopter. His first instinct? To strap on his fins and get a closer look. But the ruins proved difficult to locate, and it took repeat attempts over the course of three years to pinpoint their whereabouts. Finally, over three years later, on March 21 of this year, Sutton struck gold.
Among his finds: walled structures, some still connected to their original fortifications, and pieces of pottery. The cultural artifacts are currently being dated—a process that may confirm or deny whether the ruins could correspond to the lost city of Rhapta—but early signs are pointing toward a possible match.
Adding to the evidence is archaeologist Felix Chami from the University of Dar es Salaam. His work with villagers in nearby Jojo have recently confirmed sightings of “underwater houses” in the vicinity. Members of the Jojo community insist that the sunken city was the work of their Portuguese ancestors, but Chami believes there is a strong possibility that the Portuguese had built on top of someone else’s ruins.
While more official research gets under way, diving enthusiasts and history buffs can explore the site for themselves. To do so, they can head to neighboring Thanda Island—a newly opened, $10,000 per night private island retreat—where guests can take guided dives around the mysterious formations. Unlike research stations associated with most archaeological discoveries of this magnitude, Thanda makes a for a plush base camp. Among other things, the five-bedroom villa is stocked with its own spa, cigar humidor, copper bath tubs, and a glass-walled pool.