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)

International photographic competition, which runs in association with the Royal Botanic Gardens in Kew, London, awards special prize for the best close-up images. Here: Winner – Mayflies by Petar Sabol, Goričan, Croatia. (Photo by Sabol Petar/International Garden Photographer of the Year)

The three pals dressed to the nines enjoyed a boozy night out in Leeds, United Kingdom on August 27, 2021. Boozed-up Brits flocked to bars across the country to enjoy the start of the three-day break. (Photo by Nb press ltd)

Infantrymen of the US First Army shake hands with Russian soldiers on the broken bridge over the Elbe after the link-up at Torgau, Germany. The US soldiers are (L-R): Pfc. John A Metzger, Delbert E Philpott, and Pvt. Thomas B Summers; all are from A Company, 271st Regiment. (Photo by Allan Jackson/Getty Images). 04-1945

Japan's electronics equipment maker MuRata Manufacturing Co., Ltd's showcased their bicycle-riding robot “MuRata Boy” during the CEATEC Japan 2006 exhibition on October 3, 2006 in Chiba, Japan. The “MuRata Boy” robot can ride up a 25-degree slope, stop without losing its balance and make an S-curve without falling. (Photo by Koichi Kamoshida/Getty Images)

A priest of the ancient Samaritan community, wrapped in a prayer shawl, holds up a Tora scroll as worshippers pray during the holy day of Shavuot on Mount Gerizim on June 12, 2011 in Nablus, West Bank. Shavuot is a Jewish religious holiday and commemorates the anniversary of the day God is said to have given the Torah to the Israelites. (Photo by Uriel Sinai/Getty Images)

The photographer holds up a Samsung Galaxy Tab 7.7 tablet at the Samsung hall at the IFA 2011 consumer electonics and appliances fair the day before the fair's official opening on September 1, 2011 in Berlin, Germany. The IFA 2011 will be open to the public from September 2-7. (Photo by Sean Gallup/Getty Images)

A participant works on a laptop on the first day of the 28th Chaos Communication Congress (28C3) – Behind Enemy Lines computer hacker conference on December 27, 2011 in Berlin, Germany. The Chaos Computer Club is Europe's biggest network of computer hackers and its annual congress draws up to 3,000 participants. (Photo by Adam Berry/Getty Images)