A young visitor interacts with a baby hippopotamus swimming in its enclosure at the Berlin Zoo on January 1, 2018. Tourists and locals flocked to the zoo in the German capital on the unseasonably warm first day of the year. (Photo by Odd Andersen/AFP Photo)

A German special anti-tank gun is ready to fire during the army maneuvers in Silesia, Poland, on September 22, 1928. (Photo by AP Photo)

“Jallikattu is a bull taming sport played in Tamil Nadu as a part of Pongal celebrations on Mattu Pongal day. Annually, jallikattu is held from January to July, played first in world-famous Palamedu, near Madurai on January 15 followed by “Alanganallur-jallikattu” in Alanganallur, near Madurai on 16 January. There is a specific breed of cattle bred for this purpose known as Jellicut and from the place of a big breeder Pulikulam”. – Wikipedia. Photo: Bull tamers try to control a bull during the bull-taming sport called Jallikattu, in Palamedu, about 575 kilometers (359 miles) south of Chennai, India, Tuesday, January 15, 2013. (Photo by Arun Sankar K./AP Photo)

Alee Harrison, 13, wears the tv series “Doctor Who” on her legs as she works on a painting for Operation Blue Pride. (Photo by Greg Lovett/The Palm Beach Post)

Germany's Kira Walkenhorst (L) taps Germany's Laura Ludwig during the women's beach volleyball qualifying match between Germany and Canada at the Beach Volley Arena in Rio de Janeiro on August 9, 2016, for the Rio 2016 Olympic Games. (Photo by Leon Neal/AFP Photo)

Revellers battle with tomato pulp during the annual “Tomatina” (tomato fight) festival in Bunol near Valencia, Spain, August 31, 2016. (Photo by Heino Kalis/Reuters)

A girl poses at an entrance of her house next to a bomb dropped by the U.S. Air Force planes during the Vietnam War, in the village of Ban Napia in Xieng Khouang province, Laos September 3, 2016. From 1964 to 1973, U.S. warplanes dropped more than 270 million cluster munitions on Laos, one-third of which did not explode, according to the Lao National Regulatory Authority. (Photo by Jorge Silva/Reuters)

Men selling sheep wait for customers at a local livestock market, ahead of the Eid al-Adha festival, in Lagos, Nigeria September 11, 2016. (Photo by Akintunde Akinleye/Reuters)