America's National Parks Service celebrates its birthday on August 25 (101 years old this year!), but you don't need a special occasion to celebrate their beauty every day of the year.

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One park not to be missed is, located at the convergence of the Colorado and Mojave Deserts in California. The park spans almost 800,000 acres and is famous for its tree-sized yuccas, called Joshua Trees.These, according to Lonely Planet, who thought the upward stretching branches resembled the Biblical prophet Joshua pointing the way to the promised land. Tourists visiting the weekend of April 18 will also . is also a great destination to explore. Not only is it, but it also , such as jackrabbits (which cool off through their ears), javelinas, desert tortoises and a variety of reptiles and birds.

should visit , where in July and August, some of the park's 2,200 wild brown bears can be seen searcing for food. Many of the dominant males are known to fish for sockeye salmon at Brooks Falls, which features a . is also a great wildlife refuge, home to . Visitors also have an easy time spotting some of these creatures because many of the mammals, such as deer, are alrge and conspicuous.

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So whether you want to take advantage of this fee-free weekend,or take a special wildlife tour, check out our slideshow above to see all 59 of America's incredible national parks.