Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

Myanmar revellers take part in celebrations on the fifth and last day marking Thingyan, a water festival which brings in the country's new year, in Yangon on April 16, 2016. The Buddhist festival of water pouring symbolizes spiritual cleansing and begin the new year free from worldly impurities with celebrants devoting the four days of Thingyan in merry making of water dousing until the eve of new year. (Photo by Romeo Gacad/AFP Photo)

Galapagos – Rocking the Cradle: Four major ocean currents converge along the Galapagos archipelago, creating the conditions for an extraordinary diversity of animal life, April 25, 2016. The islands are home to at least 7,000 flora and fauna species, of which 97 percent of the reptiles, 80 percent of the land birds, 50 percent of the insects and 30 percent of the plants are endemic. (Photo by Thomas P. Peschak for National Geographic/World Press Photo)

Belarusian schoolchildren, who are members of a pro-government Young Pioneer movement, perform with drums as they take part in a meeting to mark the 95th anniversary of their organisation in Minsk, Belarus May 19, 2017. (Photo by Vasily Fedosenko/Reuters)

2016 Rio Olympics, Gymnastics training, Rio Olympic Arena, Rio de Janeiro, Brazil on August 4, 2016. Close up of the feet of Rebecca Downie (GBR) of United Kingdom as she trains on the beam. (Photo by Dylan Martinez/Reuters)

Children play in their grandmother's garden in a suburb of Budapest, Hungary, Thursday, July 21, 2022. Hungary has experienced several heat waves since mid June with day-time temperatures rising to 40 degrees Celsius and remaining at tropical levels through the night. In fact, the country recently shattered record for its hottest night ever when temperature of 25.4 C was measured in Budapest on July 26. (Photo by Anna Szilagyi/AP Photo)

An Afghan burqa-clad woman carries a child as she walks along a road in Herat on October 1, 2023. (Photo by Mohsen Karimi/AFP Photo)

A group of children run into a fountain on the South Bank on August 1, 2011 in London, England. Temperatures in the capital reached around 27 degress today and are expected to hit 30 degrees by Wednesday. (Photo by Dan Kitwood/Getty Images)