Milena Pino, 15, puts on makeup prior to taking part in a speed competition with horses at the International Livestock Fair Show in Havana March 21, 2015. (Photo by Alexandre Meneghini/Reuters)

An undercover police officer, who had been marching with anti-police demonstrators, aims his gun at protesters after some in the crowd attacked him and his partner in Oakland, California December 10, 2014. Police said more than 100 demonstrators marched in Berkeley, California, which has a history of social activism. Under cloudy skies, turnout was smaller than earlier in the week, when demonstrators in the area threw rocks at police and shut down a major freeway. (Photo by Noah Berger/Reuters)

A visitor poses for a photograph in front of a 3D painting depicting a Japanese Imperial army soldier at a 3D art gallery in Beijing January 16, 2015. (Photo by Kim Kyung-Hoon/Reuters)

This Thursday, January 22, 2015 photo made with a long exposure shows the glow from a Noctiluca scintillans algal bloom along the seashore in Hong Kong. The luminescence, also called Sea Sparkle, is triggered by farm pollution that can be devastating to marine life and local fisheries, according to University of Georgia oceanographer Samantha Joye. Noctiluca itself does not produce neurotoxins like other similar organisms do. But its role as both prey and predator tends can eventually magnify the accumulation of toxins in the food chain, according to R. Eugene Turner at Louisiana State University. (Photo by Kin Cheung/AP Photo)

The Arabian mare “Jenny” curiously sniffs at the child of Raphael Wöllstein, who is on his way to the train, on her daily walk through the Fechenheim district of Frankfurt, Germany on March 8, 2019. Her owner opens the stable door for the 22-year-old horse every morning. Then the animal can decide for itself where it wants to spend the day. So that nobody thinks she's escaped, a sign with the inscription “My name is Jenny, didn't run away, just go for a walk” is on the halter. (Photo by Boris Roessler/dpa)

A woman is detained by security forces after looting broke out during an ongoing blackout in Caracas, Venezuela, March 10, 2019. (Photo by Ivan Alvarado/Reuters)

A member of an Egungun masquerade group, his identity obscured under his ornate costume in Ouidah, Benin on March 13, 2019. The exclusively male practitioners, found across Yoruba culture, use dance and spinning in the belief that they will summon the spirits of ancestors. (Photo by Massimo Rumi/Barcroft Images)

Tango instructor Fernando Waisberg (R) and Isabella Waisberg (L) pose for a photograph during a Tango lecture session in Taipei, Taiwan, 14 April 2019 (issued 18 April 2019). Taiwan has developed its own Tango, with a strong Japanese influence; the accompanying music features lyrics in Taiwanese and Mandarin, the pace slower and simpler than the original. Taiwanese Tango is now a popular phenomenon among people over 40, and is also a subject little studied inside and outside of the island. (Photo by Ritchie B. Tongo/EPA/EFE)