Enlisted personnel are identified by way of their various 'E' grades ranging from E-1 to E-9. For those service branches recognizing a Warrant Officer rank, 'W' grades range from W-1 to W-5. Likewise Officers are scaled from O-1 to O-10.
China has quite a collection of natural bridges, including one that experts say has the longest span of any natural bridge in the world. The Fairy Bridge (Xianren Qiao), in southwestern China's Guangxi Zhuang Autonomous Region near the border with Vietnam, has a 400-foot span.
Aloba Arch is one of the most magnificent natural arches in the world, located in the Ennedi Range of the Sahara Desert in Chad. This is not a natural bridge, but a very large alcove arch. Aloba Arch has a span of approximately 250 feet, but perhaps more striking than the span, is the sheer height of the arch.