Probably you have seen photos of the Grand Canyon , the great valley in the desert country of Arizona. But you must go there yourself to feel its true size and beauty. The Grand Canyon is one of the greatest natural wonders of the world The Colorado River formed the Grand Canyon over millions of years.Slowly,the river cut down through hard rock.At the same time,the land was rising.Today,the canyon is 1.5 kilometres deep and 445 kilometres long.The oldest rocks at the bottom of the canyon are more than 1 billion years old.The width varies from about 200 metres to 29 kilometres across.The rim or top of the canyon is about 2,300 metes above sea level on the South Rim,and about 3,000 metres on the other side,the North Rim.As a result,there are different kinds of plants and animals on opposite sides of the canyon.The South Rim is a dry desert country.The North Rim has tall forests. The canyon looks different at different times of day, and in different seasons and weather. At sunrise and sunset the red, gold, brown and orange color1s of the rocks are especially clear and bright. In winter, the canyon is partly covered with snow. The view from the South Rim of the Grand Canyon is the best. Most visitors come here and stay in campgrounds or hotels. Every point along the canyon's edge offers a different view. The North rim of the Canyon is quieter. It takes all day to drive there from the South Rim because there is only one bridge across the Colorado River. On the way, you go through Navado Indian lands, and a color1ful pink desert called "The Painted Desert". If you want to have a visit to the Grand Canyon, you'd better go to   _  .
the North Rim the South Rim the bottom Navado Indian Lands