Aerial view of the Lena River (Siberia, Russia).The Lena River is the eleventh-longest river in the

Aerial view of the Lena River (Siberia, Russia).The Lena River is the eleventh-longest river in the world, and theeasternmost of the three great Siberian Rivers that flow into theArctic Ocean.  It begins in the mountains of south-central Russia,flows northwards for about 4,400km, and splits into many streamsacross the tundra that empty into the Laptev Sea in the Arctic Ocean. Because it is so far north, the Lena is frozen for seven months outof the year, but during its short summer it thaws into a wetland thatis ecologically very important.Hundreds of lakes and ponds can be found in the tundra.  This isbecause only around 20-40cm of the ground thaws in summer, with thepermafrost below stopping the lakes from draining away. -- source link

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