Martin Lacey Jr. with a lion during the premiere of the Circus Krone program “Circus der Preistraeger” at Circus Krone on February 2, 2016 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

Two three-month-old female white Bengal tiger cubs play with a zoo keeper in their enclosure at the Buenos Aires' Zoo, in Argentina, on April 17, 2014. Captive white Bengal tiger Cloe, gave birth to three cubs – two females and one male – on January 14, 2014. (Photo by Juan Mabromata/AFP Photo)

A female member of the Ahbab Al-Mustafa Battalion holds a gun as she undergoes military training in Aleppo's Salaheddine district, June 24, 2013. (Photo by Muzaffar Salman/Reuters)

An Iraqi soldier stands guard as a pipeline burns in the background after an explosion 30 kilometers (20 miles) northeast of Tikrit, Iraq, Monday, February 11, 2008. (Photo by Bassem Daham/AP Photo)

A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

Members of La Legion, an elite unit of the Spanish Army, including a goat they use as a pet wait for the start of a military parade as they celebrate a holiday known as “Dia de la Hispanidad” or Hispanic Day in Madrid, Wednesday, October 12, 2016. (Photo by Daniel Ochoa de Olza/AP Photo)

Meanwhile, over on Portobello beach, members of the Upsala circus take a stroll before their fringe debut, Ping-Pong Ball Effect in Edinburgh, England on August 1, 2017. (Photo by Murdo Macleod/The Guardian)

South Vietnamese-born designer Quasar drives the six-foot long square-shaped plastic car he built and which is scheduled to be a hit with the young driving set, in Paris, June 23, 1967. The car can be driven at speeds of up to 60 mph (Photo by Michel Laurent/AP Photo)