Geologists estimate the Grand Canyon to be between five and six million years old. In that time, the "big ditch" has seen its fair share of action. To chronicle it would take a book. Instead, I've taken the liberty to condense it into these 18 brief, historical highlights:

1. The discovery of spear points made by Paleo-Indian hunters indicate that men inhabited the canyon in 10,000 B.C.

2. 500 B.C. to present - Various Native American tribes have continuously lived in the Grand Canyon region. The Cohonina, Cerbat, and the Anasazi were the first to settle the area. Then came the Navajo, Paiute, and Hopi. Many of these groups were ancestors to the Hualapai and Havasupai, two tribes that today call the canyon home.

3. In 1540, Spanish conquistador Francisco Coronado happened upon the Grand Canyon.

4. The 1948-signing of the Treaty of Guadalupe made the Grand Canyon a part of the United States.

5. The first geologic survey of the canyon was in 1856 by Mr. Jules Marcou of the Pacific Railroad.

6. The first attempt to explore the canyon was in 1857 by Lt. Joseph Christmas Ives. He was commissioned by the War Department to determine if the Colorado River was navigable - and it was!

7. The first time a map included the name "Grand Canyon" was in 1868. The following year, John Wesley Powell, famously know as the "one-armed explorer" because he lost said limb to a musket ball, put together a 10-man team and led them on the Colorado River Exploring Expedition.

8. In the 1870's, greedy miners invaded the canyon looking for large deposits of copper, lead, and zinc. They eventually abandoned their efforts because the ore was too difficult to extract.

9. The 1880's brought the railroads. The Atlantic and Pacific Railroads put up stations in Flagstaff, AZ, and in Williams, AZ, leading to an small influx of visitors.

10. Under the direction of President Benjamin Harrison, the Grand Canyon was accorded National Forest Reserve status in 1883.

11. Journalist Winfield Hogaboom drove herself and three friends to the South Rim in 1902. It was the first car to enter the Park.

12. President Theodore Roosevelt elevated the canyon to National Monument status in 1908.

13. President Woodrow Wilson promoted the canyon to National Park status in 1919.

14. In 1922, the Fred Harvey Company constructed Phantom Ranch, a small rustic commune of stone cottages located at the bottom of the Canyon along the Colorado River.

15. Cars surpassed trains in the 1930's as the preferred way to travel to the canyon.

16. In 1975, President Gerald Ford expanded the canyon's boundaries to include Marble Canyon National Monument.

17. The Grand Canyon became a World Heritage Site in 1979.

18. President Bill Clinton created the Grand Canyon-Parashant National Monument in 2000. The new monument, located adjacent to the North Rim, encompasses more than a million acres, nearly the same size as Grand Canyon National park (1.2 million acres total).

The Grand Canyon is a living history book. This brief time line is enough to get you started as plan your vacation's list of things to do and see. More information is available at any of South Rim's fabulous information centers. Or ask a Park Ranger. These folks act as stewards of the land and are sure to have an answer. They'll also help keep from being buried in a guidebook so you can do what you came for: Enjoy the Park's stunning natural beauty with eyes wide open.

Travel expert Keith Kravitz writes exclusively about the Grand Canyon and its surroundings. If you found this article useful, consider checking out his Grand Canyon tour reviews at: http://www.GrandCanyon123.com