Impressive aerial view of Hoover Dam. For those who don't know: Hoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada
The Manitou Incline in Colorado. A vertical wonder that gains feet in elevation in less than a mile. The Manitou Springs Incline is a popular hiking trail rising above Manitou Springs, Colorado, near Colorado Springs.