in Qayyarah, about 31 miles (50 km) south of Mosul, Iraq, Sunday, October 23, 2016.in Qayyarah, some 50 kilometers south of Mosul, Iraq, Sunday, Oct. 23, 2016. Islamic State fighters torched a sulfur plant south of Mosul, sending a cloud of toxic fumes into the air that mingled with oil wells the militants had lit on fire to create a smoke screen. (Photo by Marko Drobnjakovic/AP Photo)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)

A hot air balloon in the shape of children's comic Rupert Bear is seen tethered before a tethered flight at the Bristol International Balloon fiesta in south west England, Britain, August 10, 2018. (Photo by Adrian Sherratt/The Guardian)

A participant of the sled dogs race in action with the dogs in Stroehen (Lower Saxony), Germany, 18 October 2015. It is the first round of the North German Championship. (Photo by Peter Steffen/EPA)

A woman rides a mini bicycle through crowds of Santa costumes in a park during the annual SantaCon on December 10, 2016 in London, England. The event sees hundreds of people walking the streets of London and drinking alcohol in Father Christmas and other festive costumes. (Photo by PA Wire)

An actor performs during the show “Paris de Nuit” in Santiago, Chile, 20 September 2016. The show is a combination of cabaret and circus, produced by the Recirquel Contemporary Circus Company from Budapest, and will be performed at the Mapocho Cultural station from 20 to 25 September. (Photo by Mario Ruiz/EPA)

A Pakistani farmer guides his bulls as he competes in a traditional bull race in Khunda village in the northwestern district of Attock, some 80 kilometers from Islamabad on January 3, 2015. Tens of thousands of people gather whenever there is a bull race held in Pakistan which are usually the highlight of festivals organized in rural areas of the Asian country, and attract lots of spectators due to their thrilling nature. The traditional competition attracts landlords and farmers from all around the province where the race is held, and they all bring their fastest and strongest bulls in hopes of gaining a reputation. (Photo by Aamir Qureshi/AFP Photo)

A wolf skin is on display for sale next to a painting of Russian communist revolutionary Vladimir Ilyich Ulyanov, also known as Lenin, at Izmailovo flea market in Moscow on December 3, 2017. (Photo by Mladen Antonov/AFP Photo)