2016 年落矶山山脉之旅
Landscape Arch,  Arch National Park

ZT: The longest natural rock span in the world, this arch's opening is 306 feet wide - 6 feet longer than a football field. A nine story building would easily fit
beneath this thin span. In 1991, a massive slab of rock fell from its underside, resulting in an even thinner ribbon of rock.