The Corinth Canal, Aegean Sea, Greece

The canal consists of a single channel 8 metres (26 ft) deep, excavated at sea level (thus requiring no locks), measuring 6,346 metres (20,820 ft) long by 24.6 metres (81 ft) wide at the top and 21.3 metres (70 ft) wide at the bottom. The rock walls, which rise 90 metres (300 ft) above sea level, are at a near-vertical 80° angle. The canal is crossed by a railway line, a road and a motorway at a height of about 45 metres (148 ft). In 1988 submersible bridges were installed at sea level at each end of the canal, by the eastern harbour of Isthmia and the western harbour of Poseidonia.
Although the canal saves the 700-kilometre (430 mi) journey around the Peloponnese, it is too narrow for modern ocean freighters as it can only accommodate ships of a width of up to 16.5 metres (54 ft) and a depth of 7.3 metres (24 ft). Ships can only pass through the canal one at a time on a one-way system. Larger ships have to be towed by tugs. The canal is nowadays mostly used by tourist ships; 11,000 ships per year travel through the waterway.