[{SlideShowNav}] !!!Grand Canyon [{Image src='1000us.jpg' width='590' height='800' caption='Photo: Grand Canyon, Factbook, PD' alt='Grand Canyon' class='image_left'}] [{SET customtitle='Grand Canyon'}] \\ Aerial view of the Colorado River as it snakes through the majestic Grand Canyon in Arizona. The sedimentary layers exposed in the canyon date back 2 billion years!