This tour takes us from Donaueschingen-Villingen to the Danube Delta, through eight countries, along the longest river in Central Europe, past historic cities and picturesque landscapes to the Danube Delta on the Black Sea. Probably the most impressive and well-known valley breakthrough in Europe is the 100 km long cataract section with the even more famous Iron Gate, which forms the border between Serbia on the right and Romania on the left side of the Danube.