The Diolkos was an ancient Greek paved road built around 600 BCE that allowed ships to be dragged overland across the narrow Isthmus of Corinth. Rather than sailing all the way around the dangerous southern tip of Greece, which could add weeks to a journey, captains could pay to have their vessels hauled across this six-kilometer stone trackway on wooden rollers or wheeled platforms.

Think of it as a shortcut that saved enormous time and risk. The voyage around the Peloponnese peninsula involved treacherous waters that destroyed many ships. The Diolkos let merchants and naval commanders bypass these dangers entirely, pulling their boats from one side of Greece to the other in less than a day.

The road itself was an engineering marvel: its stone blocks had carefully carved grooves to guide the wheeled carts that carried the ships. Archaeologists have found sections of these grooves still visible today, more than 2,600 years later. The Diolkos remained in use for centuries, eventually becoming obsolete when the Corinth Canal was finally cut through the isthmus in 1893.

It stands as one of history's cleverest solutions to a geographic problem: when you can't sail through something, sometimes you can roll over it.