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)

Saintsetseg Jambaldorj, a member of the Tsaatan ethnic minority, one of the last remaining groups of nomadic reindeer herders in East Taiga, Mongolia, wearing a traditional deel, on July 5, 2016. (Photo by Madoka Ikegami/Barcroft Images)

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)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)

Green Bay Packers' Johnathan Calvin rides a bike to NFL football training camp on July 27, 2017, in Green Bay, Wis. (Photo by Morry Gash/AP Photo)

A woman holds an elderly woman on her back to cross a flooded street after a heavy rain in Shenyang, Liaoning province on July 14, 2017. (Photo by Fred Dufour/AFP Photo)

A member of the pro-government “red shirt” movement attacks a Buddhist monk outside the National Anti-Corruption Commission office in Nonthaburi province, on the outskirts of Bangkok March 24, 2014. Members of the movement attacked the monk after he shouted complaints to the group blocking a road near the National Anti-Corruption Commission. (Photo by Chaiwat Subprasom/Reuters)

Iraqi firefighters try to stop the fire of burning oil wells in Kirkuk, northern Iraq, 02 June 2016. Two Khabbaz oil field wells in Kirkuk Province, northern Iraq, exploded by suspected insurgents, a security official said. (Photo by EPA/Stringer)