The Grand Canyon reminds us constantly that we are merely specks in the history of the earth and universe. When asked, I tell people the hardest thing about running the canyon is not the rapids ...

But Arizona isn't the only place where an ambitious explorer can find a Grand Canyon. NASA’s Lunar Reconnaissance Orbiter has snapped pictures of two gigantic basins on the lunar surface.

With 22 national parks and monuments to its name, Arizona boasts some of the most astonishing landscapes in the country, from the Grand Canyon to the towering buttes of Monument ...