China has some of the most spectacular highways in the world, including the world's longest trans-oceanic bridge, highways built into steep mountainsides, and roads with breathtaking turns. Three highways of note are the Tianmen Mountain Winding Highway in Hunan Province, which has 99 turns over 11km ranging from 200m to 1,300m in elevation; the Aizhai Highway also in Hunan, considered the most beautiful mountain road; and the Tarim Desert Highway in Xinjiang, the longest highway crossing a desert at 552km. China also has impressive bridges and elevators, like the Bailong Elevator in Hunan, the world's tallest outdoor elevator.