The house of the Brothers Grimm in Steinau, Germany where the Grimm family lived from 1791-1796. Guided tours are possible. Links to Steinau Tourism Page in English.
Trier (founded by the Romans - oldest town in Germany). Very fun to stroll the streets or peek into the cathedrals. I saw the robe of Jesus here in 2012. www.RiverCruiseGuru.com for free assistance with your river cruise.