Yosemite has served to preserve a region of unmatched landscape for posterity. Best known for the Yosemite Valley, the park extends far beyond it, to its eastern border at the summits of the Sierra Nevada. Two major rivers that flow through the park, the Merced and the Tuolumne, originate from snow melting off those peaks.
Wilderness permits are required of all overnight backpackers and can be obtained free at the park. A Californian fishing license is required for all park waters, available in both daily and annual varieties. Ranger-naturalists provide nature walks in summer and snowshoe programs in winter.
Skiing and skating are enjoyed during winter months. Badger Pass Ski Area has both downhill and cross-country skiing. The visitor center in Yosemite Valley has exhibits and programs and is open all year.
The Website below is unofficial, but has lots of pictures.