A participant runs on stairs during a vertical run event at China World Summit Wing hotel in Beijing, China, September 19, 2015. About 800 runners took part in the event on Saturday, which takes runners up 82 floors, covering a total of 2,041 steps to a height of 330 metres, the organizer said. (Photo by Kim Kyung-Hoon/Reuters)

Iraqi children play with a ball on a street blocked with burning tyres, amid a general strike in the southern city of Basra, on November 25, 2019. The demonstrations rocking the capital and Shiite-majority south since October 1 are the biggest grassroots movement the country has seen in decades. Sparked by outrage over rampant government corruption, poor services and lack of jobs, they have since gone straight to the source: calling out the ruling system as inherently flawed and in need of a total overhaul. (Photo by Hussein Faleh/AFP Photo)

An orphan plays with her new hula hoop during the food and toy distribution, for total about 500 orphans in 11 orphanages, by National Muslim COVID-19 Response Committee to celebrate Eid al-Fitr, the Muslim holiday which marks the end of the fasting month of Ramadan at Good hope markazil Banatil Islamia orphans centre in Nairobi, Kenya, on May 25, 2020. (Photo by Yasuyoshi Chiba/AFP Photo)

A swimmer reacts after finishing his competition in a pool carved into thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2015. The swimming competition was held on the official launch day of the Harbin International Ice and Snow Sculpture Festival. (Photo by Kim Kyung-Hoon/Reuters)

Pedestrians have a snowball fight in Times Square following a mandatory shutdown of the streets at 11 p.m. on January 26, 2015 in New York City. New York, and much of the Northeast, is bracing for a major winter storm which is expected to bring blizzard conditions and 10 to 30 inches of snow to the area. (Photo by Alex Trautwig/AFP Photo)

Newly-wed couples attend their group wedding ceremony which was held as part of the Harbin International Ice and Snow Festival in the northern city of Harbin, Heilongjiang province January 6, 2016. As many as 15 couples attend this mass wedding ceremony. (Photo by Aly Song/Reuters)

A picture taken on August 7, 2017 shows a Snow Leopard (Panthera uncia) at the NABU center (Nature and Biodiversity Conservation Union), a German organization that aims at reintroducing the panther and fighting against poaching, near the Issyk Kul lake, in the outskirts of Semenovka village, some 330 kilometers southeast of Bishkek, the capital of Kyrgyzstan. (Photo by Vyacheslav Oseledko/AFP Photo)

Kashmiri children play with snow on a wooden foot bridge in the interiors of Dal Lake in Srinagar on January 16, 2017. A cold wave has further tightened its grip in Jammu and Kashmir, with most places in the state recording sub-zero temperatures. (Photo by Tauseef Mustafa/AFP Photo)