A zookeeper feeds a hippopotamus with a watermelon in its enclosure in Belgrade's zoo, Serbia, July 20, 2015. Temperatures in Serbia have risen up to 40 degrees Celsius (104 degrees Fahrenheit), according to official meteorological data. (Photo by Marko Djurica/Reuters)

A woman wears false flag eyelashes during the St Patrick's day parade through Dublin city centre on St Patrick's day, on March 17, 2013. (Photo by Julien Behal/PA Wire)

Spectators dressed as leprechauns attend St Patrick's Day parade in Dublin on March 17, 2014. (Photo by Peter Muhly/AFP Photo)

Chamrock, an Irish wolfhound, sports a green coat as he waits for the start of the St. Patrick's Day parade on March 17, 2012 in Chicago, Illinois. Tens of thousands took advantage of record high temperatures and sunny weather to attend the city's annual St. Patrick's Day celebration. (Photo by Brian Kersey/Getty Images)

People with red hair from all over the world gather on “Roodharigendag” (Redhead Day) in Breda, The Netherlands, 07 September 2014. The Redhead Day is celebrated annually at the old Dutch city on the first weekend in September. It offers cultural events, music, a picnic, a fashion show and art exhibitions from and for the red haired community. (Photo by Arie Kievit/EPA)

A racegoer cheers on their horse at Cheltenham Racecourse for ladies day on March 16, 2011 in Cheltenham, England.

A man plays to the cameras as racegoers make their way home at the end of Ladies Day the second day of the Aintree Grand National Festival meeting on April 8, 2016 in Aintree, England. Today is Fabulous Friday and Ladies Day of the three-day meeting of the world famous Grand National Festival where fashion and dressing to impress is as important as the racing. (Photo by Christopher Furlong/Getty Images)

Stray dogs stand on tombs in Diamond Hill cemetery in Hong Kong, China, 04 April 2017. According to the lunar calendar, the Qingming Festival is observed on 04 April . The Qingming Festival, also known as Tomb-Sweeping Day, is marked by Chinese people by going to the cemetery to cleaning up tombs, bring flowers, and making offerings to their ancestors. (Photo by Jerome Favre/EPA)