A supercell thunderstorm develops, May 8, 2017 in Elbert County outside of Limon, Colorado. With funding from the National Science Foundation and other government grants, scientists and meteorologists from the Center for Severe Weather Research try to get close to supercell storms and tornadoes trying to better understand tornado structure and strength, how low-level winds affect and damage buildings, and to learn more about tornado formation and prediction. (Photo by Drew Angerer/Getty Images)

In this photograph taken on February 18, 2016, Pakistani children ride on swings in the predominantly Pashtun Korangi District of Karachi. In a rundown district of Karachi, Rabia balks at a neighbour's proposal to vaccinate her children, demonstrating one of the biggest hurdles to eradicating polio in Pakistan by the end of the year: confused and frightened parents. (Photo by Asif Hassan/AFP Photo)

A farmer harvests broccoli in the town of al-Ansariyeh south of Sidon, Lebanon March 15, 2016. (Photo by Ali Hashisho/Reuters)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Costumed dancers parade on the first day of the annual Qoyllur Rit'i festival on May 27, 2018 in Ocongate, Peru. Every year, since 1783 in the Sinakara Valley at the foot of Mt Ausagante, the Qoyllur Rit'i, or “Snow and Star” festival draws tens of thousands of pilgrims from across the Peruvian Andes and beyond to what is the biggest religious gathering of its kind. Since 1780 the event merged into a mosaic of indigenous, pagan and Catholic worship when an image of Jesus appeared on a boulder after the death of a young shepherd. (Photo by Dan Kitwood/Getty Images)

A palomino horse's mane is seen against the sky at Spancil Hill horse fair in Spancil Hill, Ireland June 23, 2018. (Photo by Clodagh Kilcoyne/Reuters)

A girl uses a mattress as a raft during the flood after the Xepian-Xe Nam Noy hydropower dam collapsed in Attapeu province, Laos July 26, 2018. At least 26 people were killed and over 3,000 people stranded after a hydroelectric dam built collapsed in southeastern Laos, destroying thousands of homes and leaving an unknown number of dead. (Photo by Soe Zeya Tun/Reuters)

A model is seen backstage before the Rochas Spring/Summer 2019 women's ready-to-wear collection show during Paris Fashion Week in Paris, France, September 26, 2018. (Photo by Gonzalo Fuentes/Reuters)