A model in Mongolia costumes prepares backstage in Xiangshawan Desert, also called Sounding Sand Desert on July 18, 2013 in Ordos of Inner Mongolia Autonomous Region, China. Xiangshawan is China's famous tourist resort in the desert. It is located along the middle section of Kubuqi Desert on the south tip of Dalate League under Ordos City. Sliding down from the 110-metre-high, 45-degree sand hill, running a course of 200 metres, the sands produce the sound of automobile engines, a natural phenomenon that nobody can explain. (Photo by Feng Li)

“A monowheel is a one-wheeled single-track vehicle similar to a unicycle. However, instead of sitting above the wheel, the rider sits either within it or next to it. The wheel is a ring, usually driven by smaller wheels pressing against its inner rim. Most are single-passenger vehicles, though multi-passenger models have been built.

Pedal-powered monowheels were built in the late 19th century; most built in the 20th century have been motorized. Some modern builders refer to these vehicles as monocycles, though that term is also sometimes used to describe motorized unicycles. Today, monowheels are generally built and used for fun and entertainment purposes, though from the 1860s through to the 1930s, they were proposed for use as serious transportation”. – Wikipedia

Photo: Cycle inventor Kerry McLean poses for the photographer 2000 in Walled Lake, Michigan. The “Monocycle” is equipped with a 40-horsepower engine, 4ft tire and is expected to reach speeds upwards of 100 mph. (Photo by Bill Pugliano/Liaison)

A couple walk on a catwalk in a flooded Saint Mark Square during a period of seasonal high water in Venice on October 29, 2018. Venice frequently floods when high winds push in water from the lagoon, but Monday's levels are exceptional and forecast to rise even higher, to 160 centimeters (nearly 63 inches) by mid-afternoon. (Photo by Manuel Silvestri/Reuters)

The Anthem Veterans Memorial was created in Anthem, Arizona, in order to commemorate the service and sacrifice of the US soldiers that have lost their lives in order to bring peace and democracy to many nations throughout the world. Without these brave souls so many countries around the world would not be able to enjoy the fruits of Western Democracy. These pillars serve as a place of honor for military veterans, their friends and family, and to those people who want to pay their respect to the courageous men and women who continue to serve the United States. (Photo by Anthem Community Council)

In this Saturday, July 4, 2015 photo, Israeli and Russian members of knight clubs cook their breakfast before the reenactment of the Battle of Hattin in Lavi Forest, northern Israel. About a third of the participants arrived with their elaborate gear from Russia. The project is supported by the Lower Galilee Regional Council. (Photo by Oded Balilty/AP Photo)

Visitors check photos on a smartphone during the activity "Birgu by Candlelight" in the medieval city of Birgu, also known as Vittoriosa, outside Valletta, Malta, October 10, 2015. During the annual event, most street lights are switched off and the city is lit up by candlelight, creating a magical ambience, according to its local council. (Photo by Darrin Zammit Lupi/Reuters)

Discovered in 1952 by French bio-speleologist Henri Coiffait, the waterfall and accompanying sinkhole were fully mapped in the 1980s by the Spéléo club du Liban. The cave is also known as the "Cave of the Three Bridges." Traveling from Laklouk to Tannourine one passes the village of Balaa, and the "Three Bridges Chasm" (in French "Gouffre des Trois Ponts") is a five-minute journey into the valley below where one sees three natural bridges, rising one above the other and overhanging a chasm descending into Mount Lebanon. During the spring melt, a 90–100-metre (300–330 ft) cascade falls behind the three bridges and then down into the 250-metre (820 ft) chasm. A 1988 fluorescent dye test demonstrated that the water emerged at the spring of Dalleh in Mgharet al-Ghaouaghir.