Huanglong travertine terraces, Sichuan, China

This striking Sichuan feature is called the Five Color Pool, but in truth it's part of a nearly 700-pool palette containing countless colors. With its apex above the 11,000-foot elevation mark, this travertine terrace system spills over a 2-mile stretch of the deep gully known as Huanglong ('yellow dragon,' for the pools' resemblance to a scaly beast slithering down the valley). One of the most striking and extensive sites of its kind, Huanglong has been recognized as a World Heritage Site since 1992.