No. 9 Lena River
This river is considered the 10th longest river in the world, being about 2,734 miles long. It runs through Eastern Siberia, and joins two other rivers to flow into the Laptev Sea. The river is frozen during winter, and when spring comes, the ice melts, producing floods because ice blocks hinder the flow of water. The last tragedy took place during 2007, when the Lena River flooded, leaving more than 1,000 houses under water.
