The Badlands National Park, one of the most popular attractions in western South Dakota, contains one of the world’s richest fossil     1    (bed). Scientists believe that 33 million years ago, a watering hole was located in the Badlands and that a drought forced mammals to travel long distances     2    (detect) water. Ancient horses, turtles, and hornless rhinos once     3     (live) here. Nowadays, the park is mainly home    4     mammals like big horn sheep, antelopes, and deer,     5    wander the 244,000 acres of the park. The park is also a reintroduction site of the endangered black-footed ferret(雪貂), one of the world’s     6    (rare) mammals.

Visitors can enjoy hiking on eight routes from 400 meters to 160 kilometers long and     7    (camp) at Cedar Pass Campground with attractive scenic views. Badlands National Park has no formal reservation system, but visitors ought to obey some rules. Firstly, apply for     8     pass ahead of time. Maps are     9    (strong) recommended and are available for purchase in the Badlands bookstore. Besides, campfires     10    (ban) under any circumstances. Finally, remember to take away all garbage, including toilet paper, and all human waste must be buried in a small hole 6 inches deep and a minimum of 200 feet from any water source.