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)

An Iranian girl walks past a mural with Iran's national flag in a street in Tehran, Iran, 03 December 2020. Iranian president Rouhani said that his government does not agree with the parliament's draft bill to quit the nuclear deal, to reduce nuclear commitment and to increase nuclear activities. The development comes after the assassination of Iranian nuclear scientist Mohsen Fakhrizadeh earlier this week. (Photo by Abedin Taherkenareh/EPA/EFE/Rex Features/Shutterstock)

A female motorcycle cop directs traffic wearing crash helmet, Haywarket Square, Boston, Massachusetts, 1979. (Photo by Spencer Grant/Getty Images)

A man looks on from the sea as Italian model and actress Elisa Sednaoui poses for photographers a day before the 72nd Venice Film Festival in Venice, Italy, September 1, 2015. Sednaoui will be hosting the opening and closing ceremonies of the film festival. (Photo by Stefano Rellandini/Reuters)

A Cambodian resident wearing a mask attends a ceremony at Pring Ka-Ek village on the outskirts of Phnom Penh, Cambodia, 09 June 2016. Villagers organized a ceremony to continue their local traditions by paying respect to the Neakta Pring Ka-Ek (Spirit house) to prevent them from diseases and to achieve abundant rice harvests and other agricultural yields. (Photo by Mak Remissa/EPA)

Women dressed up as Vikings attend the annual Viking festival of Catoira in north-western Spain on August 5, 2018. The festival re-enacts past Viking raids in the area and is celebrated annually on the first Sunday of August. (Photo by Miguel Vidal/Reuters)

A man holds a child after rescuing him from a kindergarten affected by a fire at a commercial building, in Ningde, Fujian province, China, September 16, 2015. According to local media, more than 260 people were evacuated due to the fire, which broke out Wednesday morning. No causalities have been reported and the cause of it is still unknown. (Photo by Reuters/China Daily)

A member of the “Castellers Minyons de Terrassa” adjusts her belt before forming a human tower or ÒcastellÓ during the festival of the patron saint of Barcelona “The Virgin of Mercy” at Sant Jaume square in Barcelona, Spain, September 20, 2015. The formation of human towers is a tradition in Catalonia dating back to the 18th century. (Photo by Susana Vera/Reuters)