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)

Atsushi Abe and Yumi Adachi from Japan perform in the synchronised swimming mixed duet technical routine preliminary at the Aquatics World Championships in Kazan, Russia July 25, 2015. (Photo by Michael Dalder/Reuters)

Members of Team Italy are seen underwater as they perform in the synchronised swimming team free routine preliminary at the Aquatics World Championships in Kazan, Russia July 28, 2015. (Photo by Michael Dalder/Reuters)

Boeing 747-400 of KLM in approach for the “Princess Juliana” airport, Netherlands Antilles Sint Maarten on July 2, 2002. (Photo by LUPOO/Ullstein Bild via Getty Images)

One of a members of the Franciscan Action Network and immigration rights activists is arrested during a demonstration calling for the end of immigrant detention on Capitol Hill in Washington, U.S., July 18, 2019. (Photo by Joshua Roberts/Reuters)

A cosplayer dressed as Domino attends 2019 Comic-Con International on July 20, 2019 in San Diego, California. (Photo by Quinn P. Smith/Getty Images)

A girl plays with her pet goats at a village some 200 kilometers away from Kolkata, in Tumpa Mondal, India on July 21, 2019. (Photo by Tumpa Mondal/Xinhua News Agency/Barcroft Media)

Avigail Collins and Daisy Lowe attend Liudmila X Avigail Collins Launch Party on July 13, 2017 in London, England. (Photo by Kintzing.com for Liudmila x Avigail Collins/SilverHub/Rex Features/Shutterstock)