Siberian river Lena turned out to be 70 km longer, that it was considered to be, say Russian geographers.
      
      A group of Russian students and teachers recently returned from an expedition to the river's headwaters in the Baikal-Lena reserve park, located in the Irkutsk region.
      
      Lena forms from numerous brooklets, which appear at waterlogged slopes of the Baikal Ridge and then mix into a large river. In such a case, the longest brook is consedered to be the river's head.
      
      Researchers studied satellite images and found which brook was the real head of the giant river. Then their hypothesis was confirmed during the expedition, where researchers found the place, where the spring came out of the rocks.
      
      Thus, Russian geographers found out that real length of the Lena river was 4 thousand 472 kilometers. Lena ranks tenth among world's longest rivers and second in Russia after the Ob' river.
      
      Source: BBC