New York City policemen tangled with demonstrators at a subway station on the opening day of the New York World's Fair, April 22, 1964. Youths attempted to stall the train, which was headed from the city to the fairgrounds, as a form of protest on behalf of civil rights for blacks. (Photo by Charles Gorry/AP Photo)

Arctic wolves in their new enclosure in the wildlife park in Hanau, Germany, 10 February 2015. The pack is one of the park's main attractions, which specializes in local and European breeds. (Photo by Boris Roessler/EPA)

Young girls attend a training session in MGFSO Olympic reserve school in Moscow on May 30, 2016. (Photo by Kirill Kudryavtsev/AFP Photo)

A reveller smiles as she walks in the rain at Worthy Farm in Somerset during the Glastonbury Festival in Britain, June 28, 2015. (Photo by Dylan Martinez/Reuters)

Spectators dance in the infield before the 150th running of the Kentucky Derby at Churchill Downs in Louisville, KY on Saturday, May 04, 2024. (Photo by Jabin Botsford/The Washington Post)

A female Indian rhinoceros called Maruska eats a vegetable birthday cake on her first birthday celebration at the Plzen Zoo on February 3, 2015 in Plzen, Czech Republic. (Photo by Ladislav Nemec/Isifa)

A chevrotain or mouse deer feeds in its enclosure at Zurich Zoo, Zurich, Switzerland, October 17, 2012. (Photo by Patrick B. Kraemer/AP)

Ary Borges feeds his tiger named Dan at his home in Maringa, Brazil, Thursday, September 26, 2013. Borges is in a legal battle with federal wildlife officials to keep his endangered animals from undergoing vasectomies and being taken away from him. He defends his right to breed the animals and says he gives them a better home than they might find elsewhere in Brazil. (Photo by Renata Brito/AP Photo)