In June of 1924, George Mallory and Andrew Irvine left Advanced Base Camp at 21,000 feet to attempt to be the first to summit Mt. Everest. They never returned. In deed, Everest was not successfully summitted until 1953 by Edmund Hillary. Many believed Mallory and Irvine had achieved the summit but no evidence of this was ever found. In 1999, a National Geographic Society expedition found Mallory's remarkably well preserved body on the North face of the mountain, but his camera with possible documentation of his summit was not located. Considering the top of the Wissahickon Gorge is at an elevation of about 200 feet, oxygen tanks will not be needed and I think we will have much better luck. Hope you can join us.