A couple covered in mud wait for it to dry at the Salt-works lakes near the Black Sea town of Burgas in Bulgaria on July 25, 2019. Thousands of tourists visit the red salt lakes for mud baths, which are believed to help the healing of muscular disorders and rheumatism. (Photo by Nikolay Doychinov/AFP Photo)

A youth rides his bicycle at Times Square, in New York City, U.S., August 14, 2019. (Photo by Lucas Landau/Reuters)

The Vattenfall Solar Team car “Nuna” from the Netherlands competes in the Challenger class on Day 2 of the 2019 Bridgestone World Solar Challenge at Elliott on October 14, 2019 in Elliott Australia. Teams from across the globe are competing in the 2019 World Solar Challenge – a 3000 km solar-powered vehicle race between Darwin and Adelaide. The race starts on the 13th of October in Darwin in the Northern Territory and travels the Stuart Highway to Port Augusta and then via Highway 1 to finish in the City of Adelaide in South Australia. (Photo by Mark Evans/Getty Images for SATC)

A three-metre-tall painted bronze sculpture, Seated Man 2016, by the artist Sean Henry, is lifted into its new home on July 23, 2019 at Yorkshire Sculpture Park in Wakefield, England. (Photo by Christopher Thomond/The Guardian)

Revellers attend the Saint Patrick's Day parade on March 17, 2019 in Dublin, Ireland. Saint Patrick, the patron saint of Ireland is celebrated around the world on St. Patrick's Day. According to legend Saint Patrick used the three-leaved shamrock to explain the Holy Trinity to Irish pagans in the 5th-century after becoming a Christian missionary. (Photo by Charles McQuillan/Getty Images)

Dutch supermodel Doutzen Kroes during the 3rd ABOUT YOU Awards at Bavaria Studios on April 18, 2019 in Munich, Germany. (Photo by Gisela Schober/Getty Images for ABOUT YOU)

An Indigenous man stands under a water fountain outside a government building in Brasilia, on April 26, 2019, during the last day of a protest camp. Approximately 4,000 indigenous people from different tribes are taking part in protests during the Indigenous National Mobilization (MNI) week, a mobilization which seeks to tackle territorial rights' negotiations with the government. (Photo by Carl De Souza/AFP Photo)

Spot, a robot with dog-like movements, walks past a dog in Cathedral Square in Erfurt, Germany on April 20, 2021. Security service provider Ciborius, a provider of robotic security solutions with artificial intelligence, presented its artificial employee with high-resolution 360-degree all-round camera, ultra-bright LED light and a light detection system on Domplatz. (Photo by Michael Reichel/dpa)