EuroVelo 6, named the "Rivers Route", is a EuroVelo long-distance cycling route that runs along 3,653 km some of Europe's major rivers, including much of the Loire, some of the Saône, a short section of the upper Rhine and almost the entire length of Europe’s second longest river, the Danube — from the Atlantic coast of France to the city of Constanța on the Black Sea.
The EV6 traverses ten countries, from the mouth of the Loire eastward along that river to the Saône, across the border to Switzerland, along the Rhine to Lake Constance, north into Germany, down the Danube and through Austria, Slovakia, Hungary, Serbia, Croatia, Bulgaria, and Romania to the Danube Delta, before terminating at Constanța on the Black Sea.
Wikipedia https://en.wikipedia.org/wiki/EV6_The_Rivers_Route
Official Website https://cyclingeurope.org/european-routes/eurovelo-6/
Address 82 Árpád út, Kismaros 2623, Hungary
Coordinates 47°49'28.901" N 19°1'6.294" E