The 99km-long Nord-Ostsee-Kanal reaches the Baltic Sea from the North Sea at Kiel, with some 60,000 ships passing through every year. It's easy to view the Schleusen (locks) at Holtenau, 7km north of Kiel. The viewing platform here is open from sunrise to sunset. There’s a museum on the southern side of the canal. To get to the locks, take bus 11 to Wik, Kanal. A free ferry shuttles back and forth between the southern and northern banks.
Inaugurated in 1895, the canal is now the third-most trafficked in the world, after the Suez and Panama canals.