Travertine terraces are some of the most bizarre-looking geological formations on Earth. The rock that makes up these unique formations is a type of limestone commonly deposited by mineral springs through a process of rapid precipitation of carbonate minerals.
Travertine has been used as a building material since the time of the ancient Romans, and it was even used in the construction of St. Peter's Basilica and Square in Vatican City. However, the most stunning structures this rock has been known to produce are the travertine terraces!
The most iconic example of the travertine terrace phenomenon is found in Pamukkale (above) in Denizli Province of southwestern Turkey. Pamukkale, which means "cotton castle" in Turkish, is located near the ruins of the ancient city of Hierapolis, and it has been a popular bathing spot for thousands of years. Pamukkale and Hierapolis were jointly named a World Heritage Site in 1988, and the area remains one of the country's most beloved tourist destinations to this day.
Pamukkale shouldn't hog all the glory, however. From China to Guatemala to Iran, the Earth has quite a collection of natural travertine treasures. Continue below for more instances of this geological wonder!
Huanglong, Sichuan, China
Semuc Champey, Guatemala
Detail of Pamukkale, Turkey
Mammoth Hot Springs, Yellowstone National Park, Wyoming
Photo: Siamaksabet/Wikimedia Commons
Badab-e Surt, Mazandaran, Iran
Photo: chensiyuan/Wikimedia Commons
Aerial view of Huanglong, Sichuan, China
Bagni San Filippo, Tuscany, Italy
Photo: Don Graham/Flickr
Detail of Mammoth Hot Springs, Yellowstone National Park, Wyoming
Plitvice National Park, Croatia
Photo: ( Waiting for ) Godot/Flickr
Sunbathers at Pamukkale, Turkey