Linking the North Sea to the Baltic, the Kiel Canal is a vital trade route that carries more traffic than any canal in the world. Entering the Canal from the Elbe River, traverse the low-lying marshlands, lakes and meadow-dotted hills of bucolic Schleswig-Holstein (you'll see lots of Holstein cows!) reaching Kiel Fjord in the Baltic. This historic waterway was built in 1895 and is a marvel of engineering.