The 3rd part of this trip was a cruise down the Danube from Vienna to the Black Sea. In 2012 I went on a cruise from Passau to Budapest, a very scenic part of the river so I wanted to go down the rest.
Hungarian Parliament Building.
The Danube is navigable for 2414 km. It goes through or is the border for 10 countries, Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldavia and Ukraine. Of these it is the border between Bulgaria and Romania or flows through Romania for 1075 km and Moldavia for 800 metres where the river Prut enters the Danube.