According to my Silk Road guide book, Tiemenguan (Iron Gate) is the only spot of any cultural significance in Korla. The actual physical gate (as opposed to the mountain pass it's located in) was completely destroyed during the Cultural Revolution, although it was recently rebuilt. The name, Iron Gate, comes from the fact that a toll gate/army outpost was located here along the only Silk Road route leading north of the Tien Shan mountains. Located in a narrow mountain pass, the outpost was easily defended and almost impossibe for traders to avoid.