Dug through the Isthmus of Corinth at sea level, the canal doesn’t need locks. Submersible bridges at each end can be lowered to allow passage for boats.
Dimitrios Pallis
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Why did this Greek canal take 2,500 years to build?

Stunning photos illuminate how the Corinth Canal became an engineering marvel—with an unexpected fate.

Maps byMatthew W. Chwastyk
Words bySam Kean
Published February 9, 2026

People complain about construction delays, but even the most sluggish modern transit project has nothing on Greece’s Corinth Canal, which didn’t open until 2,500 years after it was announced.

Four miles long, with sheer rock walls that rise nearly 260 feet from the waterline, the canal connects the Gulf of Corinth with the Saronic Gulf, theoretically saving mariners a journey of hundreds of nautical miles around the Peloponnesus peninsula. A Corinthian ruler named Periander is said to have first proposed it around 600 B.C. He settled instead for a limestone-paved road with a rudimentary railway, on which small ships could be carted across the isthmus.

Julius Caesar and Caligula contemplated reviving the canal scheme, but it was the Roman emperor Nero, in A.D. 67, who broke ground. His thousands of laborers—slaves, prisoners, soldiers—dug some two miles of trenches before Nero’s ouster and suicide put an end to the project. It took 18 more centuries until a Greek company, armed with steam power and dynamite, finished the job.

Alas, the canal opened in 1893 as steel-hulled ships were replacing smaller iron ones. Only 70 feet across in spots, the passage was too narrow for the shipping industry’s increasingly beefy vessels, and it never caught on as a major conduit for commerce.

A large red cargo ship is guided by tugboat through the Corinth Canal
Tugboats guide larger vessels through the narrow passage. In 2019 a cruise ship called the M.S. Braemar became the biggest boat to squeeze through, with only two or three feet of clearance on either side.
Dimitrios Pallis

Today it’s primarily a tourist attraction. Following five years of sporadic closures during a project to stabilize its rockfall-prone walls, it’s expected to reopen this spring. Some 15,000 ships will pass through this year, says the canal’s general manager George Zouglis, and the fact that most will carry sightseers instead of cargo doesn’t make the waterway any less of a marvel. “Every captain on every ship going through,” Zouglis says, “they live this history that connects two eras, the ancient with the modern.”

A version of this story appears in the March 2026 issue of National Geographic magazine.