The Grand Canyon was once connected from the south rim to the north rim by way of a trans-canyon telephone system. The telephone poles were made of 2" threaded pipe with pipe fittings for the elbow, tees, and other configurations. Standard glass insulators were used to keep the transmission through the copper wires from grounding. Much of the old telephone line is gone now but there are still some poles, insulators, and wire remaining. The section of remaining line in this panorama along the North Kaibab corridor trail just upstream from Lower Ribbon Falls. The trees and brush along the outflow of Ribbon Falls can be seen in the back ground just right of the transmission wires opposite from the sun.