The Yosemite National Park in the United States is one of the most beautiful reserves of the country.

Beautiful landscapes, amazing waterfalls and jawdropping rocky formations are a common sight here.
  The park, which is managed by the National Park Service, covers an area of 747,956 acres (3,026.87 km2) and reaches across the western slopes of the Sierra Nevada mountain chain. Over 3.7 million people visit Yosemite each year.

 Yosemite Valley is open year-round, but much of the remaining park is closed in late autumnbecause of snow and re-opens in mid to late spring. Open-air tours around Yosemite Valley and the Mariposa Grove of giant sequoias are available. Many people enjoy short walks and longer hikes to waterfalls in Yosemite Valley, or walks amongst giant sequoias in the Mariposa, Tuolumne, or Merced Groves.

 Water activities are plentiful during warmer months. Rafting can be done through the Yosemite Valley on the Merced River. There is also a swimming pool available at Curry Village.

Source