An Indian student warms up during the 44th Samartha Summer Sports Coaching Camp organized by Shree Samarth Vyayam Mandir in Mumbai, India, 25 April 2018. Mallakhamba arose in the western state of Maharashtra centuries ago. It was originally practiced by wrestlers and soldiers as a strength training exercise. (Photo by Divyakant Solanki/EPA/EFE)

A seagull eats a piece of dried fish of a man's hand during sunset at Bang Pu seaside resort in Samut Prakan province on the outskirts of Bangkok, Thailand, 13 January 2019. Every year during the cold winter months between October to March thousands of seagulls migrate to Bang Pu seaside from Siberia to escape the harsh winter. (Photo by Diego Azubel/EPA/EFE)

Aerial view of tourists in life vests and rubber rafts in the Grand Canyon of western Henan, Sanmenxia, China on August 5, 2017. (Photo by Imaginechina/Rex Features/Shutterstock)

A woman looks at head of bluefin tuna on display in front of a store at Tsukiji fish market in Tokyo, Monday, February 19, 2018. The large bluefin are particularly valuable in Japan, where they are considered a premium sushi and sashimi fish. A single fish sold for more than $1.75 million at an auction in Japan in 2013. (Photo by Koji Sasahara/AP Photo)

This picture taken on March 1, 2016 shows a man running a mobile pig mating service and waiting outside a customer's home with his male pig in a cage pulled behind his motorcycle in the northern province of Bac Ninh. (Photo by Hoang Dinh Nam/AFP Photo)

A boy flies his kite in a cemetery in the Vila Operaria Favela of Rio de Janeiro, Brazil, July 9, 2016. (Photo by Nacho Doce/Reuters)

People walk along the Neva River at sunset in St.Petersburg, Russia, Tuesday, December 6, 2016. The temperature in St.Petersburg is –9C ( 15.8 °F). (Photo by Dmitri Lovetsky/AP Photo)