Josh Gates ventures to the waters off Zanzibar in search of Rhapta, a wealthy Roman trading outpost that vanished from history over a thousand years ago. Once a thriving emporium where gold, ivory, tortoise shell, and ornate ceramics flowed through its ports, Rhapta served as the Roman Empire's southernmost commercial hub along the East African coast. Gates explores two competing theories about the city's location: one archaeologist has identified a graveyard of ancient shipwrecks that may indicate the site, while another team believes they've found submerged harbor walls visible only at low tide. The expedition takes Gates diving in remote waters and navigating the historic labyrinth of Stone Town on Zanzibar, where he meets local researchers working to pinpoint this legendary port.
Rhapta is mentioned in ancient Greek and Roman texts, including Ptolemy's geography and the first-century *Periplus of the Erythraean Sea*, which describes it as a significant trading center, though its exact location has never been confirmed archaeologically. The city likely disappeared due to a catastrophic event, possibly a tsunami, during the Middle Ages, leaving no above-ground traces. What makes this expedition compelling is the convergence of new underwater discoveries—potential harbor structures and shipwreck evidence—that could finally place Rhapta on the map and expand understanding of Roman commercial reach into sub-Saharan Africa. Finding the city would reveal artifacts and trade networks that connect ancient Rome to the African interior in ways not fully documented by historical records.
Chole Bay, Mafia Island
Tanzania · archaeological
Gates comes ashore at Chole Bay to meet underwater archaeologist Bridget Buxton and pottery expert Alexandra Ratzlaff, who outline their approach to finding Rhapta by locating ancient shipwrecks reported by local fishermen in nearby waters.
Mafia Island
Tanzania · archaeological
Gates travels to Mafia Island, the primary search zone for Rhapta, identified by its location at approximately seven degrees south latitude matching Ptolemy's coordinates. He investigates multiple sites around the island with two separate archaeology teams.
Mwamba Ukuta (Rocky Wall), Mafia Island
Tanzania · archaeological
Gates investigates a mysterious linear rock formation known locally as Mwamba Ukuta, which emerges from the Indian Ocean only at low tide. Dr. Felix Chami and archaeologist Caesar Bita claim it represents the outer harbor walls of Rhapta, constructed of Roman hydraulic concrete, though Gates remains skeptical it is man-made.
Offshore shipwreck site, Mafia Island
Tanzania · archaeological
Gates and Bridget Buxton dive coordinates provided by local fishermen and discover a collection of ceramic vessels alongside ballast stones, indicating the likely remains of a shipwreck. The recovered pottery is assessed as post-medieval, predating but not conclusively linked to Rhapta.
Ras Kisimani, Mafia Island
Tanzania · archaeological
Gates joins Buxton and Ratzlaff at Ras Kisimani, the westernmost peninsula of Mafia Island, where low tide exposes an extraordinary density of artifacts including pottery spanning multiple centuries and cultures, a stone anchor, a coin, a possible loom weight, Chinese ceramics, Portuguese imports, tower foundations, and a shell layer interpreted as a tsunami deposit.
Zanzibar
Tanzania · archaeological
Josh dove into remote waters searching for the lost ancient trading city of Rhapta, exploring shipwrecks and ruins visible only at low tide.