Short answers, pulled from the story.
The Volga River is 3,531 kilometers long. It rises in the Valdai Hills in Tver Oblast at 225 meters above sea level and flows through Central Russia and Southern Russia before emptying into the Caspian Sea below Astrakhan at 28 meters below sea level.
The Volga is called Волга-матушка, or Volga-Matushka (Mother Volga), reflecting its deep symbolic role in Russian national identity. Russian literature and folklore have invoked this name for centuries, with works by Aleksandr Ostrovsky, Maxim Gorky, and Nikolay Nekrasov all tied to the river.
The Battle of Stalingrad, fought at the city now known as Volgograd on the big bend of the Volga, is widely described as the bloodiest battle in human history. Hitler sought control of the Volga to cut Soviet access to Caspian Sea oil fields and block the vital transport route between central Russia and the Absheron Peninsula.
On the 28th of August 1941, Stalin had the Presidium of the Supreme Soviet pass a decree ordering the resettlement of Germans living in the Volga region. Approximately 400,000 Volga Germans were accused of collective collaboration, deported to Siberia and Central Asia, and forced into labor camps, where thousands died. They were officially cleared of the accusation in 1964.
The name Volga derives from the Proto-Slavic root vòlga, meaning wetness or moisture, a root preserved in many Slavic languages. The Scythian name for the river, Rahā, also meant wetness, and the same meaning appears in the related Avestan term Raŋhā.
Eight major hydroelectric reservoirs were built on the Volga during the Soviet era. The Kuybyshev Reservoir is the largest in Europe by surface area. The Rybinsk Reservoir was, at the time of its construction, the largest artificial lake in the world. Their creation flooded the town of Mologa entirely and submerged monasteries dating from the 15th and 16th centuries.