1. Spree   Berlin   Cologne   Washington D.C.   Nanking   Hint Half-n-half Clue   2. Nile Nile Blue Nile   Montreal   Cairo   Lisbon   Washington D.C.   Half-n-half Clue   3. Danube   Rome   Bern   Vienna   Kinshasa   Half-n-half Clue   4. Hudson   Berlin   Montreal   Washington D.C.   New York   Half-n-half Clue   5. Potomac   Nanking   Kinshasa   Paris   Washington D.C.   Half-n-half Clue   6. Tagus Tagus Tejo   Rome   Nanking   Lisbon   Bern   Half-n-half Clue   7. Tiber Tiber Tevere   Nanking   Rome   Paris   Lisbon   Half-n-half Clue