First lady Michelle Obama (R), joined by daughters Sasha Obama (C) and Malia Obama, is presented with the official White House Christmas Tree on November 25, 2011 in Washington, DC. The tree, a 19-foot-tall balsam fir, was grown on Schroeder's Forevergreens farm near Neshkoro, Wisconsin. (Photo by Brendan Hoffman/Getty Images)

A man tries to stop two bulls from locking horns during a bullfight in the eastern emirate of Fujairah October 17, 2014. There are no matadors or picadors, but bulls locking horns with each other draw big crowds to bullfights in the United Arab Emirates (UAE). An hour's drive from the dancing water fountains of Dubai's glitzy downtown, hundreds of fans gather in Fujairah to watch bulls fighting, or perhaps more accurately head butting, with honour rather than money at stake. The UAE sport involves two bulls locking horns in a three-to-four minute Sumo-wrestling-like fight that usually ends with no bloodshed. (Photo by Ahmed Jadallah/Reuters)

Ma Jiaqi, 5, and her mother arrive at Beijing Railway Station for their train to Changchun of Jilin province, in Beijing, China, January 25, 2016. According to traffic police, over 2.9 billion trips will be made around China during the 40-day Spring Festival travel rush, which started on January 24. (Photo by Jason Lee/Reuters)

People look at home-made armoured vehicle look-alikes on a street in Shenyang, Liaoning province, November 12, 2014. A man surnamed Zhang and his friends converted two cars into these two vehicles, for his son, and will be displaying them on show at a local park. The cannons on the vehicles can fire paintballs and smoke shells, local media cited Zhang as saying. (Photo by Reuters/Stringer)

The rear of the Chevorlet Chaparral 2X Vision Gran Turismo concept car at its world debut at the Los Angeles Auto Show in California, November 19, 2014. The annual event is open to the public beginning November 21. (Photo by Lucy Nicholson/Reuters)

People take pictures of 30 Rockefeller Plaza as it is lit in the colors of the Democratic and Republican parties ahead of the U.S presidential election in Manhattan, New York, U.S., November 7, 2016. (Photo by Andrew Kelly/Reuters)

An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

A one-horned rhino walks on the street of Sauraha, a tourism hub in southwest Nepal’s Chitwan district on July 10, 2018. (Photo by Sunil Sharma/Xinhua News Agency/Alamy Stock Photo)