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The Strait of Otranto has seabed depths of about 800 meters at its shallowest and…

2026-08-08 · 05:12 UTC ·@aakashgupta ·1 min read

Brief

The Strait of Otranto’s extreme depths (≈800–1,000 m) and 72 km width make a conventional bridge infeasible: the deepest existing bridge foundation is 65 m, and repeating Messina‑style 3.3 km spans (designed for 120 m depths; approved 1971 at €13.5B) would require about 22 world‑record spans with foundations far beyond any precedent. Norway explored a tethered floating tunnel; today a Durrës–Bari ferry (~9 hours) is the realistic link.

Why it matters

The Strait of Otranto has seabed depths of about 800 meters at its shallowest and exceeds 1,000 meters in channels, while the deepest bridge foundation ever built is 65 meters—making conventional piers physically impossible.

Key details

  • The crossing is 72 km versus Hong Kong–Macau’s 55 km (mostly under 40 m); engineers solved deep piers for the Messina Strait (120 m at piers) with a 3.3 km suspension span—approved 1971, costed €13.5 billion, and construction only began 55 years later.
  • Scaling Messina‑style spans across Otranto would need roughly 22 consecutive world‑record spans with foundations up to ~12× deeper than ever attempted; Norway instead studied an unbuilt tethered floating tunnel, and the practical current option is a Durrës–Bari ferry (~9 hours).
Source evidence

The deepest bridge foundation ever built stands in 65 meters of water. The stretch of sea between Italy and Albania is 800 meters deep at its shallowest point, and the channels pass 1,000.

That one number is why this bridge will never exist. The rest of the math only gets wilder.

The Strait of Otranto is 72 km across. The longest sea crossing on Earth, Hong Kong to Macau, runs 55 km over water that mostly stays under 40 meters deep, so engineers could sink piers like fence posts. At Otranto, a tower would need to climb 800 meters through open sea before touching air. That is nearly a full Burj Khalifa underwater, with an actual bridge tower still to build on top.

Italy already fought a smaller version of this problem. The Messina strait to Sicily is only 3 km wide, but 120 meters deep at the pier sites, too deep for mid-water supports. The solution was to design the longest suspension span in human history, 3.3 km, purely to keep both towers on dry land. That project was approved in 1971, costs €13.5 billion, and construction is finally starting 55 years later.

Now scale that up. Crossing Otranto with Messina-style spans would take roughly 22 of them back to back, each one a world record, most with foundations in water 12x deeper than anything ever attempted.

Norway ran into the same physics with its 550-meter fjords and gave up on bridges completely. The concept they settled on, a floating tube tethered 30 meters below the surface, has never been built anywhere on Earth.

Until someone builds one, the answer is a ferry from Durrës to Bari that makes the crossing in about 9 hours. Geography still wins some arguments.

Unamuno 📜 (@UnamunoAgain)

oye pregunta seria por qué no hacen un puente entre Italia y Albania en lugar de tener que dar toda la vuelta?

— https://nitter.net/UnamunoAgain/status/2085805927576264894#m