String theory: big problem for small size

String theory is the most promising candidate theory for a unified description of all the fundamental forces that exist in nature. It provides a mathematical framework that combines quantum theory with Einstein's general theory of relativity. The typical size of a string is of the order of 10-33 cm, called the Planck length. But due to this extremely small size of strings, nobody has been able to detect it directly in the laboratory till today. In this paper, we have presented a general introduction to string theory