If you are referring to the Longest Rivers in the World here goes in order of their approximate lengths: Nile, Amazon, Yangtze, Mississippi, Ob, Angara, Yellow River, and COngo River.
the longest river is the Nile that ends up in Egypt in mediteranean sea (6.600+km). the deepest one is Amazon river that ends in brazil in atlantic ocean (5.000+ meters).
There are many. The Mississippi is the largest river in the United States. The Nile is a major river of Egypt. The Thames runs through London. The Rhine in Germany.