The Kaunas Reservoir — Lithuanians call it Kauno Marios, the Kaunas Sea — is the largest artificial lake in Lithuania, stretching 84 kilometres up the flooded valley of the Nemunas River. From Rumsiskes on its northern shore, the water feels genuinely sea-like: wide, open, and moody under grey skies. In summer, the beaches on its banks fill with swimmers and sunbathers from Kaunas and Vilnius.
The reservoir was created in 1959 by damming the Nemunas near Kaunas as part of a Soviet hydroelectric project. Villages, farmsteads, and a large portion of Lithuania's agricultural heritage were submerged in the process — a fact that lends the reservoir a slightly melancholy history alongside its recreational appeal. Boating and kayaking are popular on the calmer stretches, and the shore paths make for good cycling.