The United States is home of one of the seven natural wonders of the world, the Grand Canyon. Carved by the Colorado River in a process that took millions of years, the Grand Canyon stretches for 446 kilometers over the northwestern corner of the state of Arizona. The canyon is 1,828 meters deep measured from its highest point, and 24 kilometers across at its widest point.

One significant feature of the canyon is the geologic history that can be studied there. The walls of the canyon are made up of distinct layers of rock that were formed during three eras of geological time. Some of the rocks at the bottom are 2 billion years old.

The plant and animal life is another important feature of the park. Many species of plants, mammals, birds, amphibians, reptiles and fish live within the Grand Canyon. Some of these species are unique to the area.

It is believed that people came to the canyon as far back as 10,000 years ago. A group of people called the Desert Culture began living in the area about 8,000 years ago. Later, a people called the Anasazi settled in the area, eventually leaving sometime in the 12th century A.D. Ruins of the homes they built still exist today.

In 1540, a Spanish explorer named Garcia Lopez de Cardenas became the first European to see the Grand Canyon. Cardenas was part of an exhibition wandering thorough the present day southwestern United States searching for the seven cities of gold, rumored to be located there. Unable to find a way to the bottom of the canyon, Cardenas turned back the way he had come.

It was not until the 19th century that anyone explored the Grand Canyon extensively. John Wesley Powell, a geology professor, led expeditions down the Colorado River through the canyon on two separate trips between 1869 and 1872, and gathered information about the area.

In the 1893, the president of the United States designated the Grand Canyon as a forest reserve. Later, it was made a national monument, and in 1919, the Grand Canyon became a national park. More recently, in 1979, the Grand Canyon was designated a World Heritage Site.

The spectacular views and diverse wildlife bring many people to the Grand Canyon every year. In 2003, there were 4.5 million visitors.

For those who want to explore the Grand Canyon, helicopter and plane tours, river tours, and mule rides are available. Many visitors also hike the trails on foot, or simply take advantage of the views that can be seen from the top of the canyon.

By Mary Adair