Hikers can also access two National Scenic Trails including of the Pacific Crest Trail in the southern unit of the park and of the Pacific Northwest Trail that passes through the northern unit. The north and south Picket Ranges, Mount Triumph, Eldorado Peak and Boston Peak regions are popular backcountry camping zones. Unlike most US national parks, there are no places within North Cascades National Park where one can drive to a campground. There are many vehicular access camp grounds in Ross Lake National Recreation Area and in surrounding national forests. All overnight camping is considered backcountry camping and camping areas are protected to prevent overcrowding. Backcountry camping spots can be reserved in early spring only; walk-up permits can be obtained at the Wilderness Information Center near Marblemount. Since the vast majority of the park is designated wilderness, the goal is to ensure all hikers and backcountry travelers enjoy the opportunities for solitude. Group sizes are limited to parties of less than a dozen on what are known as trail and camping corridors, and in more remote areas off trails, groups larger than six are not permitted. Bicycles are allowed in the park but only on the same roads that vehicles are allowed on. No mountain bike access is allowed on hiking trails. Hiker/biker camping is available at Newhalem Campground, Colonial Creek, and near Stehekin. Mountaineering High quality climbing routes on the numerous cliffs, ice and other challenges make the park a favorite destination for many mountaineering enthusiasts. While some peaks and cliffs can be accessed fairly easily, the most remote ones entail a multi-day excursion, challenging for even experienced mountaineers. The park has banned the installation of any new fixed anchors such as pitons, and only removable anchors such as chocks and cams are permitted. This clean climbing has been implemented to help protect the resource, since fixed point anchors deface the rock and are considered intrusive. With much of the rock climbing and mountaineering done above the tree line, the effort to protect alpine ecosystems is of paramount importance. Leave No Trace policies are strictly enforced and encouraged, such as camping only on bare rock, using only a camp stove, storing food safely where animals cannot get to it, and carrying out or properly burying human waste as necessary. Mountaineering in the North Cascades was first popularized by Fred Beckey; at age 15 he was the first to