Short answers, pulled from the story.
The Neman is 937 kilometers long, making it the fourth longest river in the Baltic Sea basin. It rises in central Belarus, flows through Lithuania, and then forms the northern border of Russia's Kaliningrad Oblast before draining into the Curonian Lagoon near the Baltic Sea.
The river is called Neman in Russian, Nioman in Belarusian, Nemunas in Lithuanian, Niemen in Polish, and Memel in German. The German name Memel derives from the indigenous name used when Teutonic Knights built the settlement of Memelburg at the river's mouth around 1250.
Napoleon Bonaparte and Tsar Alexander I signed the Treaty of Tilsit in 1807 on a raft moored in the Neman because neither ruler would step onto the other's shore. The river served as neutral ground for the meeting.
Nemunas Loops Regional Park was founded in 1992 to preserve the distinctive river bends the Neman makes near the Punia forest in Lithuania. Near Prienai, the river traces a 17-kilometer teardrop-shaped loop that comes within 1.2 kilometers of closing on itself. The loops follow underlying tectonic faults and are a source of local mineral springs.
The Deutschlandlied, written in 1841, references the Memel (Neman) as the eastern boundary of a hoped-for unified Germany. The song's first stanza reads "From the Meuse to the Memel." Germany's Weimar Republic adopted it as the official national anthem around the same time the Treaty of Versailles, in 1919, made the river a new international border.
A Swedish Environmental Protection Administration report rates the Neman's water quality in Lithuania as moderately polluted to polluted. The problems differ by country: oil products and nitrogen dominate in Belarus; lignosulphates, nitrogen, and biological oxygen demand in the Kaliningrad section; and in Lithuania the Kaunas Hydroelectric Power Plant barrage is a documented pressure on the riparian ecosystem. The dam at Kaunas, built in 1959, lacks fish ladders and has depleted Atlantic salmon runs.