Short answers, pulled from the story.
The Rhine is approximately 1,232 kilometers long, confirmed by the Dutch Rijkswaterstaat in 2010. A 1932 German encyclopedia incorrectly listed the length as 1,320 kilometers, a figure believed to be a typographical error that persisted in official publications for nearly 80 years before being corrected.
The Rhine traditionally takes its source from Lake Toma, near the Oberalp Pass in the Swiss canton of Graubunden, at an elevation of 2,345 meters above sea level. This lake feeds the Anterior Rhine, one of two headwater streams that merge near Reichenau in Tamins to form the Rhine proper.
The Rhine passes through Switzerland, Liechtenstein (as a border), Austria (briefly), Germany, France (as a border along Alsace), and the Netherlands before emptying into the North Sea. During its course it forms six different country borders.
The Rhine Falls, located below Schaffhausen in Switzerland, is the most powerful waterfall in Europe. It sits on the High Rhine section, between Lake Constance and Basel.
The Romans defined the Rhine as the boundary between Gaul and Germania, making it the northern inland frontier of the empire. Emperor Augustus ordered his stepson Drusus to establish 50 military camps along the river beginning in 12 BC, and the Romans maintained up to eight legions at five bases along its banks. The first settlement on the site of modern Cologne, Oppidum Ubiorum, was founded in 38 BC.
The Rhine-Meuse-Scheldt delta is the largest river delta in Europe, covering 25,347 square kilometers in the Netherlands. It began forming approximately 8,000 years ago and is shaped by both river sedimentation and tidal currents. The Rhine splits into three main distributaries there: the Waal, the Nederrijn, and the IJssel.
The International Commission for the Hydrology of the Rhine Basin has warned that the Rhine could experience a massive decrease in volume, or dry up completely during drought, within the next 30 to 80 years as a result of the climate crisis.