Within Yosemite there is a cavernous granite dome called Half Dome, and generally it is extremely difficult to get a permit to hike to the top of this dome. If you are on a long-distance hike, however, obtaining permits can be a little easier, which is why a side trip to the Half Dome is highly recommended if you happen to be trekking the John Muir Trail. Photo by Travis Burke 3 / 29