Gun enthusiasts look over Smith & Wesson pistols at the NRA Annual Meetings & Exhibits on May 21, 2016 in Louisville, Kentucky. About 80,000 visitors are expected to attend the three-day event. (Photo by Scott Olson/Getty Images)

Clashes break out in the stands during the Euro 2016 Group B soccer match between England and Russia, at the Velodrome stadium in Marseille, France, Saturday, June 11, 2016. (Photo by Thanassis Stavrakis/AP Photo)

A Peru fan cheers of her team during a Quarterfinal match between Colombia and Peru at MetLife Stadium as part of Copa America Centenario US 2016 on June 17, 2016 in East Rutherford, New Jersey, US. (Photo by Chris Szagola/LatinContent/Getty Images)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)

A gory fight to the death between snarling dogs and captured wild boars. Gathered around a bamboo-walled arena, Indonesians in this remote part of Java island seem eager to watch the blood-curdling contests, known locally as “adu bagong” (boar fighting). Not surprisingly, animal rights activists are up in arms against the regular spectacle, which began in the 1960s when wild pig numbers in this area in West Java soared and they were hunted to protect crops. Here: Women share a joke as they walk to a paddy field in Cikawao village of Majalaya, West Java province, Indonesia, October 12, 2017. (Photo by Reuters/Beawiharta)

In this Wednesday, December 2, 2015 photo, Dr. Gal Kelmer, head of the department of large animals, unties a horse after its operation at the University's Koret School of Veterinary Medicine in Rishon Lezion, Israel. “Horses have an instinctive response of flight from danger”, Kelmer said. “The minute they wake up they start trying to stand and run, even if they don't have control of their limbs. So then they fall”. (Photo by Oded Balilty/AP Photo)

Stuttgart Festival of Animated Film (Internationales Trickfilm-Festival Stuttgart) 2013 official trailers.

A US soccer fan cheers during the FIFA World Cup 2014 group A preliminary round match between Brazil and Croatia at the FIFA Fan Fest in Copacabana, Rio de Janeiro, Brazil, 12 June 2014. Brazil won 3-1. The FIFA World Cup 2014 will take place in Brazil from 12 June to 13 July 2014. (Photo by Abedin Taherkenareh/EPA)