Lake Peipus the town. Near Kallaste, there is one of the largest surfacings of Devonian sandstone with a length of and a maximum height of , as well as several caves and one of the largest colonies of swallows in Estonia. Lake Peipus Lake Peipus (; ; ) is the largest transboundary lake in Europe, lies on the border between Estonia and Russia. The lake is the fifth-largest in Europe after Lake Ladoga and Lake Onega (in Russia north of St. Petersburg), Lake Vänern (in Sweden), and Lake Saimaa (in Finland). Lake Peipus represents a remnant of a body of water which
Lake Ladoga were connected by a strait or a river outlet at least until the formation of the River Neva, and possibly even much later, until the 12th century AD or so. At 9,500 BP, Lake Onega, previously draining into the White Sea, started emptying into Ladoga via the River Svir. Between 9,500 and 9,100 BP, during the transgression of Ancylus Lake, the next freshwater stage of the Baltic, Ladoga certainly became part of it, even if they hadn't been connected immediately before. During the Ancylus Lake subsequent regression, around 8,800 BP Ladoga became isolated. Ladoga slowly transgressed in its southern part