More of a pit stop than a town, the isthmus is where the Peloponnese begins. Were it not for this narrow neck of land less than 7 km (4½ miles) across, the waters of the gulf of Corinth and the Saronic gulf would meet and would make the Peloponnese an island; hence the name, which means "Pelops's island."
For the ancient Greeks the isthmus was strategically important for both trade and defense; Corinth, with harbors on either side of the isthmus, grew wealthy on the lucrative east–west trade. Ships en route from Italy and the Adriatic to the Aegean had to sail around the Peloponnese, so in the 7th century BC a paved roadway called the Diolkos was constructed across the isthmus, over which ships were hauled using rollers. You can still see remnants near the bridge at the western end of the modern canal.