Participants of the 79th edition of the annual Christmas swimming “Coupe de Noel” jump into the Lake Geneva, in Geneva, Switzerland, Sunday, December 17, 2017. More than 2000 men and women swam the 120 meters at the traditional Christmas swimming in Geneva where the water temperature was 6 degrees. (Photo by Martial Trezzini/EPA/EFE/Rex Features/Shutterstock)

Tourists ride a cable car in the form a of a Chiva, a bus used to serve rural routes, in Pitalito, Colombia, Tuesday, April 5, 2017. The ride called “La Chiva Voladora” costs about $0.70 and you zip along about 800 meters from one side of a hill to another. (Photo by Fernando Vergara/AP Photo)

Yueyaquan is a crescent-shaped lake in an oasis, 6 km south of the city of Dunhuang in Gansu Province, China. It was named Yueyaquan in the Qing Dynasty. According to measurements made in 1960, the average depth of the lake was 4 to 5 meters, with a maximum depth of 7.5 metres In the following 40 years, the depth of the lake continually declined. In the early 1990s, its area had shrunk to only 5,500 m2 with an average depth of 0.9 meter (maximum 1.3 meter). In 2006, the local government with help of the central government started to fill the lake and restore its depth; its depth and size have been growing yearly since then. The lake and the surrounding deserts are very popular with tourists, who are offered camel and 4x4 rides.

A woman walks past a giant Pac-Man in Tokyo's Shinjuku area, Wednesday, August 12, 2015. The three-meter (about nine feet and 10 inches)-tall Pac-Man and other video game characters, made of Lego bricks, were on display to promote the upcoming movie “Pixels”. (Photo by Ken Aragaki/AP Photo)

Women play soccer as the Tungurahua volcano spews a column of ash during an eruption in Huambalo, Ecuador, Saturday, March 5, 2016. Tungurahua is 16,480 feet (5,023 meters) high and has been active since 1999. (Photo by Dolores Ochoa/AP Photo)

A local man looks at a church on top of the Katskhi Pillar, rock mass about 40 meters high, in the village of Katskhi, Georgia, November 27, 2015. The church, built in the ninth century, was later abandoned and it collapsed but was rebuilt in 2003, according to local media. (Photo by David Mdzinarishvili/Reuters)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)

In this March 14, 2015 photo, tourists take pictures from a viewing area at Iguazu Falls in Brazil. From walkways and bridges, viewers can count 270 water falls almost 100 meters (330 feet) high. (Photo by Jorge Saenz/AP Photo)