Travellers ride their horse through the river during the Appleby Horse Fair on June 5, 2014 in Appleby, England. The Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685 and is one of the key gathering points for the Romany, gypsy and traveling community. The fair is attended by about 5,000 travellers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Nigel Roddis/Getty Images)

Sydney Truba, 11, of Melvindale, Michigan lies in a giant lake of mud during Wayne County's 2011 Mud Day event at Nankin Mills Park July 12, 2011 in Westland, Michigan. The annual event consists of 20,000 gallons of water mixed with 200 tons of topsoil. (Photo by Bill Pugliano/Getty Images)

The Verzasca is a Swiss 30-km long mountain river originating at Pizzo Barone and flowing into Lake Maggiore. It is known for its clear turquoise water and vibrant colored rocks, as well as its treacherous currents. The Verzasca Dam is a few kilometers upriver from this lake.

Labourers stack dried bricks inside a kiln, where they will be fired, at a brick factory on the outskirt of Sanaa, Yemen, June 1, 2016. Traditional mud brick tower houses have always been a source of pride to Yemenis, and over a year into a devastating civil war, they are also providing some much-needed jobs in the ancient capital Sanaa. (Photo by Mohamed al-Sayaghi/Reuters)

A man wearing a Guy Fawkes mask enjoys a ride on a 350-meter (1148 feet) long water slide during 2015 City Silde Festa in central Seoul, South Korea, July 19, 2015. A 350 meter-long waterslide has been installed in downtown of Seoul, the longest waterslide to be recorded in Korea, according to local media. (Photo by Kim Hong-Ji/Reuters)

An elephant calf yawns as mahouts paint elephants ahead of celebrations for the water festival of Songkran in Ayutthaya, Thailand on April 11, 2019. The annual elephant Songkran event is held to promote the tourism industry. Songkran Festival is held also to mark the Thai traditional New Year falling annually on 13 April, and it is celebrated with people splashing water and putting powder on each other faces as a symbolic sign of cleansing and washing away the sins from the past year. (Photo by Soe Zeya Tun/Reuters)