Listed as endangered on the IUCN red list of threatened species, a humphead wrasse, or Napoleon fish, swims in an aquarium during an event in Tokyo's shopping district of Ginza on August 5, 2019. (Photo by Kazuhiro Nogi/AFP Photo)

A morning fog is seen in the Siberian city of Omsk, Russia on October 8, 2019. (Photo by Alexey Malgavko/Reuters)

Gymnast Simone Biles performs a flip after throwing out the ceremonial first pitch prior to Game Two of the 2019 World Series between the Houston Astros and the Washington Nationals at Minute Maid Park on October 23, 2019 in Houston, Texas. (Photo by Tim Warner/Getty Images)

House Minority Leader Kevin McCarthy (R-CA) and U.S. President Donald Trump watch a woman carry a card announcing the rounds during a mixed martial arts fight in Madison Square Garden in New York, New York, U.S., November 2, 2019. (Photo by Joshua Roberts/Reuters)

This photo shows sunset in Eagle, Colo., Sunday, November 3, 2019. Daylight saving time ended, making sunset around 5 p.m. this time of year in Colorado. (Photo by Chris Dillmann/Vail Daily via AP Photo)

Labourers push wooden boards before carrying them to construct a temporary pontoon bridge over the Ganges river for the upcoming Hindu festival of Magh Mela in Allahabad on November 24, 2019. The Magh Mela is held every year on the banks of Triveni Sangam – the confluence of the three great rivers Ganga, Yamuna and the mystical Saraswati – in Allahabad during the Hindu month of Magh which corresponds to mid January – mid February. (Photo by Sanjay Kanojia/AFP Photo)

An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

Teeming with images of spectacular underwater scenes from around the world, Call of the Blue is the culmination of a five-year project by the photographer and ocean conservationist Philip Hamilton. This groundbreaking book includes contributions from acclaimed scientists and ocean “guardians”, who reveal what drove them to answer the call of the blue. (Photo by Philip Hamilton/The Guardian)