on the map below, the blue line represents which important european river?

po river

rhine river

danube river

english river

the Rhine River

The Rhine River begins in the southeastern Swiss Alps, flows through the German Rhineland and the Netherlands and empties into the North Sea. It is the second-longest river in Central and Western Europe. The river formed most of the northern frontier of the Roman Empire, and was equally important for the Holy Roman Empire. Nowadays, it is considered a symbol of German nationalism.

can you give me more details?

explanation:

which time period is this? or is this story fictional, i'm going to need more info to answer this question