Three Unfinished Roman Megaprojects [12:20]

Transcript

Chapter 1: Introduction

More than any other premodern culture, the Romans are associated with feats of engineering. The Pantheon. The Colosseum. The Pont du Gard. Monuments that seem to defy both gravity and time. But sometimes, even the Romans fell short of completing their most ambitious projects. Today’s video explores three of these unfinished megaprojects.

Chapter 2: Moving the Tiber

Number three. Moving the Tiber.

Without the Tiber, Rome would never have existed. The city emerged around a crossing of the river and was fed through the centuries of its apogee by grain barges towed upstream. Almost every year, however, heavy rains caused the river to flood. About three dozen floods were severe enough to be recorded by ancient historians. Cassius Dio, for example, records a flood that took place in 54 BC: “The Tiber rose suddenly, flooding not only the low-lying parts of the city, but also many neighborhoods seldom inundated. The walls of the houses, being made of mudbrick, soaked through and collapsed…Those who failed to seek higher ground were drowned in their rooms or swept away on the current. Houses weakened by the flood continued to collapse for many days afterward... (39.61.1-2)

Such damage was only the beginning. Major floods often damaged the docks and grain warehouses, causing widespread famine. Whole streets of shops were ruined. Pools and puddles bred mosquitoes and malaria. Flooding seems to have grown worse over the centuries, possibly due to deforestation and erosion.

To end the Tiber’s floods and the perennial problems caused by heavy barge traffic between Rome and Ostia, Julius Caesar proposed two plans for rerouting the Tiber. The more radical of these involved redirecting the river into a canal just below Rome. The canal would run through the Pontine Marshes, paralleling the coast, and finally reach the sea near Terracina, more than 60 km south. The more feasible of Caesar’s plans called for the Tiber to be directed around Rome. A diversionary channel would be opened just above the city, cut around the Vatican Hills, and returned to the original bed well downstream. By reducing the risk of floods, this scheme would have opened the low-lying plains along the Tiber for future development. Or so Caesar hoped — he was assassinated before work could begin.

Augustus settled for the less grandiose but more practical solution of dredging the river channel. During the reign of Tiberius, yet another serious flood inspired a plan to reduce the Tiber’s flow by diverting some of its tributaries. One tributary would be redirected north into the Arno, another would be diffused by being split into many channels, yet another would be dammed. Protests from towns near the affected rivers, however, caused the Senate to reject the proposal. The Tiber continued to flood Rome until the modern embankments were built in the late nineteenth century.

Chapter 3: Nero’s Corinth Canal

Number two. Nero’s Corinth Canal.

Sailing east from Italy, Roman ships — which almost always hugged the coast — had to detour around the Peloponnese, the southernmost part of the Greek peninsula. Besides adding days to the journey, rounding the Peloponnese was hazardous. Many vessels — including those carrying the Antikythera Mechanism — were claimed by the shoals and storms of Cape Malea. The only way to avoid rounding the Peloponnese was to cross the Isthmus of Corinth. Six kilometers wide at its narrowest point, and rising to a ridge nearly a hundred meters high, the isthmus was bridged by the Diolkos, a grooved track that allowed ships — and, more frequently, loads of cargo — to be hauled from sea to sea by teams of oxen.

The Diolkos could be used to transfer whole fleets. Marcus Antonius, grandfather of the triumvir, moved his ships over it in the first stages of a campaign against the Cilician pirates; Octavian did the same before Actium. Hauling ships over the isthmus on wheeled cradles, however, was time-consuming and difficult; and from the Greek Archaic period onward, plans for cutting a canal were discussed. Aside from the obvious technical difficulties of cutting through so much solid rock, ancient engineers believed that the sea was higher on the western side of the isthmus. Any canal, they reasoned, would thus be filled with a roaring torrent of water that would flood half the Aegean.

Julius Caesar, never one for small plans, reportedly considered building a canal across the Isthmus. So did Caligula. Only Nero, however, was megalomaniacal enough to actually begin the project. We’ll discuss his disastrous attempt to do so after a brief word about this video’s sponsor.

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Returning to our topic. Nero personally inaugurated his Corinth canal, filling the first basket of earth with a golden shovel. The actual digging was done by 6,000 Jewish prisoners of war. Under the direction of the emperor’s engineers, 32 shafts, up to 40 meters deep, were cut to inspect the nature of the rock along the planned course of the canal. Work began from both ends. On the eastern side, the workmen cut 1300 meters in from the coast; in places, the depth of the trench reached 30 meters. On the western side, the cut reached two kilometers inland. A third excavation was begun through the ridge at the center of the isthmus. Nero’s death and the ensuing civil war stopped work on the canal. The project, never resumed, became a byword for hubris. A dialogue attributed to the second-century sophist Lucian likened it to the failed canal that Alexander the Great had attempted to cut around Mount Mimas. Men, he opined, should not seek to alter what the gods have made.

Although the millionaire Herodes Atticus considered trying to complete the canal, no further work was done until the nineteenth century. Even then, despite the use of explosives and steam shovels, it took 12 years to finish the job. Since the modern canal followed the route of Nero’s, virtually every trace left by the ancient workmen has been obliterated.

Chapter 4: A Capital for Germania

Number one. A capital for Germania. Monuments to unrealized projects of conquest were scattered along the edges of the Roman world. At Inchtuthil in Scotland, archaeologists discovered the remains of an unfinished legionary fort, demolished when the legions withdrew to the future line of Hadrian’s Wall. Four thousand kilometers away, in the shadow of Mount Ararat, the ruins of a Roman-style aqueduct bear witness to Trajan’s short-lived annexation of Armenia.

Perhaps the most remarkable product of imperial overreach was built in what is now central Germany, about 100 kilometers east of the Rhine. There, near the modern village of Waldgirmes, the Romans founded a city. Though protected by a timber palisade and at least two lines of ditches, this was a civilian settlement, with no permanent garrison. The town at Waldgirmes — whose ancient name we do not know — was laid out with a classic Roman grid of streets, graded to drain into central ditches. Along those streets were warehouses, taverns, and atrium-style houses, some with lead water pipes connected to the city aqueduct. Along with fragments of glass, pottery, and other goods imported from the distant Mediterranean, the excavators found fragments of a gilded equestrian statue of Augustus, which had been poised on a pedestal of Gallic stone at the center of the forum. Four other bronze statues — presumably honoring members of the imperial family — stood beside it, facing a basilica and stoas with wooden columns.

Fragments of beams and planks preserved by the waterlogged soil allowed researchers to determine that the settlement at Waldgirmes was founded around 4 BC, soon after Roman troops reached the Elbe. The city was abandoned little more than a decade later, in the wake of the Battle of the Teutoburg Forest, when the inhabitants withdrew with the legions back to the Rhine. The buildings were burned; the head of Augustus’ equestrian statue was thrown down a well. Until 1990, when it was accidentally rediscovered, even the site of this unfinished Roman megaproject was forgotten.

[payin’ some bills]

If you’d like to see some other Roman megaprojects — including the magnificent aqueduct of Carthage — you can join me in Tunisia next spring! Besides Carthage, we’ll see Dougga — the Pompeii of Africa — the magnificent amphitheater at El Jem, and many other sites. Learn more by following the link in the description.
In June 2027, I’m going to Romania, to explore some of the Roman world’s most spectacular — and seldom-visited — ruins, including the remains of the longest ancient bridge and the tunnels of a perfectly preserved 2,000-year-old mine. There’s a link below.

My new book — Leaky Aqueducts, Battle Pigeons, and Mystery Cults — is now available in both hardcover and paperback. You’ll find additional content — including my ongoing exploration of HBO’s hit series Rome — on the Toldinstone Patreon.

Finally, don’t forget my other channels, Toldinstone Footnotes and Scenic Routes to the Past. Thanks for watching!

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