 Complete the following phrase:  Gartang Gali cliff-side hanging-stairway or Gartang Gali bridge, a 500 m long narrow wooden stairway hanging high at a height of 11000 ft on the side of a vertical ridge, lies in the narrow Nelang river valley of Jadh Ganga river canyon. After cutting a narrow horizontal U-shaped passage on the side of monolith cliff, the wooden structure was built inside it in the traditional native style. It offers great views of Nelang valley and its ecology. It was initially supposedly constructed by the Pathan traders from Peshawar. Gartang Gali, a narrow and steep gorge, was Silk Road trade route between Tibet and India. After the 