A Hawaiian cleaner wrasse provides its cleaning services to a yellowfin goatfish in a reef community off the Big Island in Hawaii. Cleaner species help rid their hosts of ectoparasites, dead tissue, bacteria and fungi. Studies have shown cleaning to play a vital role in keeping many reef ecosystems healthy. (Photo by Marty Snyderman/Caters News Agency)

A reveller reacts amid a “flour war” during the “Ash Monday” celebrations, a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter, in the port town of Galaxidi, Greece, on March 11, 2019. (Photo by Aris Messinis/AFP Photo)

Children wearing military uniform take part in a parade, held by Russian servicemen, pupils of infant and primary schools, which is a public event to honour World War Two veterans and to mark the upcoming Victory Day, in Rostov-on-Don, Russia on April 25, 2019. (Photo by Sergey Pivovarov/Reuters)

Young dancers from the Style Dance Academy perform during a Mother's Day block party in Caracas, Venezuela, Sunday, May 19, 2019. Although Mother's Day was officially celebrated the previous weekend, people in the Petare area organized the neighborhood party to celebrate the mothers of their community. (Photo by Rodrigo Abd/AP Photo)

Miss Vanjie performs during the LA Pride 2019 on June 09, 2019 in West Hollywood, California. (Photo by Matt Winkelmeyer/Getty Images)

Sharafkhaneh port and lake Urmia. Masoud Ghadiri (Iran). The summer Milky Way is very prominent in this photo. On the galaxy zone, Saturn is located besides the Lagoon nebula. On the right of the horizon, you can see the extreme light pollution of Urmia, which is caused by ever-increasing city development. (Photo by Masoud Ghadiri/National Maritime Museum)

Charli XCX performs on day three of the Pitchfork Music Festival at Union Park on July 21, 2019 in Chicago, Illinois. (Photo by Michael Hickey/Getty Images)

A unidentified woman protests at Broad Street for the pending arrival of Vice President Mike Pence at the Union League, in Philadelphia, Monday, July 23, 2018. Dozens of demonstrators dressed as characters from the novel-turned-TV series “The Handmaid's Tale” descended on downtown Philadelphia to protest Pence’s visit. (Photo by Jose F. Moreno/The Philadelphia Inquirer via AP Photo)