Three great Siberian rivers are the Ob, Lena and which other?
Ob River a side arm of the Gulf of Ob. Cities along the river include: From a confluence to a source: Ob River The Ob River (), also Ob', is a major river in western Siberia, Russia, and is the world's seventh-longest river. It forms at the confluence of the Biya and Katun Rivers which have their origins in the Altay Mountains. It is the westernmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Yenisei River and the Lena River). The Gulf of Ob is the world's longest estuary. The internationally known name
Ob River basin for transportation was particularly great before the completion of the Trans-Siberian Railway, since, despite the general south-to-north direction of the flow of Ob and most of its tributaries, the width of the Ob basin provided for (somewhat indirect) transportation in the east-west direction as well. Until the early 20th century, a particularly important western river-port was Tyumen, located on the Tura River, a tributary of the Tobol. Reached by an extension of the Ekaterinburg-Perm railway in 1885, and thus obtaining a rail link to the Kama and Volga rivers in the heart of Russia, Tyumen became an important railhead