A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

Workers demonstrate outside the factory of Hua Yang Printing Holdings Co Ltd on October 30, 2007 in Shenzhen of Guangdong Province, China. Over 1,000 workers of the company have blocked the 107 State Highway where the firm is located, to protest against their employer, who owed half a month's salary to the workers. (Photo by China Photos/Getty Images)

A visitor takes a picture of a display bearing hand prints of war heroes from the War of Resistance against Japan, at Jianchuan Museum Cluster in Anren, Sichuan Province, China, May 13, 2016. Tucked away in southwestern China's Sichuan province, a private collector stands virtually alone in exhibiting relics from the 1966-1976 Cultural Revolution. Monday marks the 50th anniversary of the start of the political movement, with no official commemorations planned. Official records whitewash the details of both periods, but admit that Mao made major mistakes. (Photo by Kim Kyung-Hoon/Reuters)

Customer Andreas Kroker looks at a 3D-printed figure of himself at the Twinkind 3D printing studio in Berlin, December 13, 2013. A 3D-printed likeness is produced by taking a 360 degree photographic scan of a person, which is then rendered into a 3D digital model and retouched to meet the requirements for printing. The printing machine uses this digital model to produce a high-resolution solid figure. Twinkind co-founder Timo Schaedel said, people often come to the session well-groomed, with fresh hair-cuts and their best clothes, “just as they used to do in the past, when they had their portrait taken in a photo studio”. (Photo by Thomas Peter/Reuters)

An Israeli missile is launched from the Iron Dome missile system in response to a rocket launch from the nearby Palestinian Gaza Strip, on March 12, 2012 near Ashdod, Israel. (Photo by Uriel Sinai/Getty Images)

In this Thursday, January 28, 2016 photo, a “child angel” doll sits on a chair in Bangkok, Thailand. The dolls, which are said to bring good luck to their owners, became a media sensation this week after a leaked memo from a Thai budget airline gave pointers on how they could be treated like passengers if they have a paid-for seat. Thai people are superstitious, and the doll phenomenon has been analyzed as a modern version of a traditional totem containing real body parts, but as a fad it seems have more in common with Furby dolls. (Photo by Sakchai Lalit/AP Photo)

An Afghan Sikh man drinks from a cup inside a Gurudwara, or a Sikh temple, during a religious ceremony in Kabul, Afghanistan June 8, 2016. (Photo by Mohammad Ismail/Reuters)