Ten Lost Roman Wonders: The World’s Longest Tunnel, Tallest Dam, Widest-Spanning Bridge & More

Apart from a few bridges that still work, the infrastructural achievements of the Roman Empire exist, for us, mostly as ruins. With a little imagination, those historic sites give us a clear enough sense of the empire’s sheer might, but if we want to go deeper, we should then look into the numerous Roman constructions that haven’t survived at all. In the video below

from his channel Told in Stone, ancient-history YouTuber Garrett Ryan gives his personal top seven “lost Roman wonders,” beginning with Trajan’s Bridge, whose length of more than a kilometer across the Danube made it the longest bridge ever built at that time: a project of ambitions befitting a man that history remembers as one of the “Five Good Emperors.”

No such status for Nero, though he did commission the Subiaco Dams. Necessary to create a series of artificial lakes beneath the infamous ruler’s villa, they were the highest dams in existence until the Middle Ages. Hadrian’s more public-minded white-marble temple at Cyzicus in modern-day Turkey was known as unusually splendid even by the standards of that genre of building; now only its foundations remain, with archaeological digs turning up the occasional fragment.

In the former Constantinople, the Church of the Holy Apostles is remembered as the second-most famous vanished early Christian church, after only the old St. Peter’s Basilica in Rome. Hagia Sophia may still be around, but the Column of Justinian that once stood between it and the Great Palace was melted down for scrap long ago.

We only know of these lost structures because we have historical attestations of their existence, most vividly in paintings: take the Pyramid of Romulus, a striking tomb that appears near the Vatican in The Vision of the Cross, which Raphael’s assistants produced after his death. Others, like the Colossus of Nero from which the Colosseum takes its name, are represented on coins. In the video at the top, Ryan covers three more “forgotten Roman megaprojects”: Claudius’ tunnel of record-making length through the mountain between the River Liris and the Fucine Lake, Trajan’s military highway through the “Iron Gates” of the Danube, and Octavian’s secret harbor at Lake Avernus. In our time, of course, there are no more emperors, Roman or otherwise, and we’re surely better off for it. But we can still admire — to use a twenty-first century concept — the state capacity they commanded.

Related content:

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How the Ancient Romans Built Their Roads, the Lifelines of Their Vast Empire

The Genius Engineering of Roman Aqueducts

The Roman Colosseum Deconstructed: 3D Animation Reveals the Hidden Technology That Powered Rome’s Great Arena

The Amazing Engineering of Roman Baths

Built to Last: How Ancient Roman Bridges Can Still Withstand the Weight of Modern Cars & Trucks

Based in Seoul, Colin Marshall writes and broadcasts on cities, language, and culture. He’s the author of the newsletter Books on Cities as well as the books 한국 요약 금지 (No Summarizing Korea) and Korean Newtro. Follow him on the social network formerly known as Twitter at @colinmarshall.