Great weather again.  Temps in the high-70s and bright sun, although it will be overcast by afternoon.  The boat docks at Koblenz, a name which derives from 'confluence' because here the Main River flows into the Rhine.

Buses take us up to Marksburg castle, the only German castle never successfully attacked.  As a result, it is in pristine condition.  "Pristine", in this case, means it looks and feels like something out of the Middle Ages.  There are few, if any, alterations beyond basic creature comforts like toilets.

It's easy to see how a fortress like this might dominate river traffic, and that domination and the tolls it brought in would have been the thing that kept this little duchy in business. 

From the town below, the castle looks even more impressive than it does from inside the walls, and it's easy to see why attacking it would be something of a problem.  Lucky for us flatlanders, buses brought us almost all the way up to its front door.  We're all glad we didn't have to walk the whole way in 70 pounds of armor.