A two-hour drive south of Kullu brings you to the entry villages of the Great Himalayan National Park, one of the largest protected wildernesses in the western Himalayas. The park is home to snow leopards, Himalayan brown bears, blue sheep, and 200-plus species of bird.
Treks of three days and up are possible from the gateway villages of Gushaini and Sai Ropa, with guides arranged through the park office. You won't see snow leopards (almost no one does), but the high pastures, glacial streams, and birch forests are spectacular even on shorter walks.