There must be a canal between the Rhine and the Danube. That seems implausible, or its a very long canal. Perhaps via the River Main.
All yours Stan. The highest point above sea level which is navigable for a sea going vessel is on the Rhine-Main-Danube Canal. Between the locks of Hilpolstein and Bachhausen (Nr. Nuremburg) the elevation is 406 metres. The canal makes inland water transport possible between Rotterdam or Antwerp and the Black Sea. the canal itself is 174 km. long. Spent many an hour on the Rhine but seldom further than Koblenz. Take it away.
Which world boxing champion was the only one to be win every single fight of his professional career (undefeated plus no ties)?