Almost 6 million people visit the Grand Canyon National Park every year, but a select few experience its full majesty by hiking rim-to-rim. Watch the dramatic changes in light, color, and perspective as you descend the North Kaibab Trail a mile in altitude to the gorge of the mighty Colorado River. Then test your endurance as you cross the river and trek up Bright Angel Trail to the South Rim. It will almost seem impossible when you look back across the canyon after hiking 25.5 miles in 10-15 hours.