Performers wearing 19th century French military uniforms fire their weapons as they attack Allied forces during a reenactment of the Battle of the Nations, in a field in the village of Markkleeberg near Leipzig October 20, 2013. The east German city of Leipzig commemorated the 200th anniversary of the largest battle of the Napoleonic Wars on Sunday by reenacting the Battle of the Nations, with 6,000 military-historic association enthusiasts from all over Europe. The decisive encounter in which tens of thousands of soldiers were killed, took place from October 17-19, 1813, just outside of Leipzig. At the height of the hostilities Napoleon fielded more than 200,000 men against an Allied force of some 360,000 soldiers which included troops from Russia, Austria, Prussia and Sweden. (Photo by Fabrizio Bensch/Reuters)

A three-month-old Sumatran tiger cub named “Bandar” shows his displeasure after being dunked in the tiger exhibit moat for a swim reliability test at the National Zoo in Washington, on November 6, 2013. All cubs born at the zoo must take a swim test before being allowed to roam in the exhibit. Bandar passed his test. (Photo by Manuel Balce Ceneta/Associated Press)

Jack, a Lurcher from Dogs Trust Salisbury, walks past a window display of models in a Dogs Trust shop window in Salisbury, as part of a campaign to discourage the impulse buying of dogs ahead of Valentine's Day, on February 10, 2014. (Photo by Matt Alexander/PA Wire)

1st prize in the People Observed Portraits Stories category. Carla Kogelman, the Netherlands. The photo shows Hannah and Alena, two sisters living in the rural village of Merkenbrechts, Austria. (Photo by Carla Kogelman/World Press Photo)

This photo provided by Netflix/naturepl.com and WWF-International shows an African Elephant (Loxodonta africana) in front of double rainbow, in Masai Mara, Kenya, included in the Netflix natural history series, “Our Planet”, in collaboration with Silverback Films and WWF. The eight-part series debuts in 2019. (Photo by Andy Rouse/Naturepl/WWF-International/Netflix via AP Photo)

A spectator at the Maslenitsa car battle, reacts during a clash, in the village of Goroshki, some 35 kilometers from Minsk, Belarus, 12 March 2016. The battle which is held at the Historical and Cultural Complex, Stalin line, is a small local competition, with participants from Belarus and Russia. (Photo by Tatyana Zenkovich/EPA)

Pallas' s cat kittens with theit mother in an enclosure at the Novosibirsk Zoo, Novosibirsk, Russia on July 11, 2018. Pallas' s cat, also known as manul, is a small wild cat native to montane steppes of the Central Asia and listed as an endangered species. (Photo by Kirill Kukhmar/TASS)

Common squirrel monkeys observe their Christmas present, a box full of mealworms, at the South America enclosure of the Budapest Zoo, in Budapest, Hungary, 24 December 2017. (Photo by Photo by Attila Kovacs/EPA/EFE/Rex Features/Shutterstock)