Tianmen Mountain in Hunan Province, China is known for its 99 sharp turns to reach the summit by road and 999 steps to climb at the end. Alternatively, a cable car rises over 4,200 feet in 7.5 km. At the top are stunning views and structures like a natural stone arch formed by a cave collapse in 263AD, a temple, and the world's highest natural water-eroded cave running through the mountain. In modern times, pilots have flown planes through the large arch opening for stunts televised around the world.