There is one rule for traffic on the Danube. The Danube is a wide, sprawling river; it’s not used for traffic across its entire width, but rather a so-called “navigation channel” (plovni put) is marked. … It’s the same on the Nile, the Mississippi, and the Amazon, all the world’s great rivers. Since all rivers are generally wide and sprawling, there are shallows, and a ship cannot navigate there. Although for laymen this isn’t clear, how it can be a river and yet not navigable. It must be marked like on ski slopes – red and green buoys are placed. We always look downstream. On the right side, red anchored buoys or lanterns are placed, which mark the right edge of the navigation channel. On the left side, green ones. They mark the left edge of the navigation channel. And traffic on the water is only allowed between that marked section.