Oka
The Oka is a river in central Russia, the largest right tributary of the Volga. It flows through the regions of Oryol, Tula, Kaluga, Moscow, Ryazan, Vladimir and Nizhny Novgorod and is navigable over a large part of its total length, as far upstream as to the town of Kaluga. Its length is 1,500 km (930 mi) and its catchment area is 245,000 km² (95,000 sq mi). The Russian capital Moscow sits on one of the Oka's tributaries ‒ the Moskva River.
Oka, related objects
Wikipedia article: http://en.wikipedia.org/wiki/Oka_(river)
Nearby cities:
Coordinates: 54°31'57"N 40°1'59"E