In this Monday, July 24, 2017 photo, a police officer walks in front of a mural during a protest demanding an end to the current pension fund system, in Santiago, Chile. Protesters say the government pension system robs retirees of fair pension payments, and are demanding a new social security system with higher payments. (Photo by Esteban Felix/AP Photo)

Armed female members of the militant Palestinian group Islamic Jihad carry Kalashnikov assault rifles as they take part in a rally to protest against US President Donald Trump's decision to recognise Jerusalem as the capital of Israel, in Gaza City on December 11, 2017. (Photo by Mohammed Abed/AFP Photo)

Ryon Healy #25 of the Oakland Athletics is covered in water by Adam Rosales #16 after he hit a walk-off home run in the ninth inning against the Detroit Tigers at Oakland Alameda Coliseum on May 7, 2017 in Oakland, California. (Photo by Ezra Shaw/Getty Images)

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)

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 young reveller participates in the annual Trinidad and Tobago Red Cross Society's Children's Carnival Competition at the Queen's Park Savannah in Port-Of-Spain, Trinidad and Tobago February 18, 2017. (Photo by Andrea De Silva/Reuters)

A South China Tiger cub meets public at Guangzhou Zoo on June 22, 2017 in Guangzhou, Guangdong Province of China. Guangzhou Zoo boasts of the successful breeding of South China Tiger cub after 15 years. (Photo by VCG/VCG via Getty Images)

Characters dressed as Elmo and Cookie Monster who pose for tips take a photo by request from a tourist (2nd R, black pants) in Times Square in the Manhattan borough of New York City, January 29, 2016. (Photo by Rickey Rogers/Reuters)