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)

A man carries an injured woman in a site hit by what activists said were airstrikes carried out by the Russian air force in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria January 9, 2016. At least 70 people died in what activists said where four vacuum bombs dropped by the Russian air force in the town of Maaret al-Numan; other air strikes where also carried out in the towns of Saraqib, Khan Sheikhoun and Maar Dabseh, in Idlib. (Photo by Khalil Ashawi/Reuters)

A Brussels Airlines aircraft prepares for landing in Cointrin airport during sunrise over the Mont Blanc in Geneva December 1, 2011. (Photo by Denis Balibouse/Reuters)

Muslim children play sack race during Eid-al-Fitr celebration in Taguig city, south of Manila July 18, 2015. (Photo by Romeo Ranoco/Reuters)

Mary McHugh mourns her slain fiance Sgt. James Regan at “Section 60” of the Arlington National Cemetery May 27, 2007. Regan, a US Army Ranger, was killed by an IED explosion in Iraq. (Photo by John Moore/Getty Images)

Participants prepare backstage before the 5th “Strongo Cup” open amateur bodybuilding tournament at the State Opera and Ballet Theatre in Russia's Siberian city of Krasnoyarsk, November 1, 2014. Participants from all over Russia took part in the tournament competing in bodybuilding, body fitness and bikini fitness disciplines. (Photo by Ilya Naymushin/Reuters)

A gun is seen next to the body of a man was killed in a shootout with police in Manila, Philippines early October 21, 2016. According to the police, sachets containing substance believed to be drug shabu (Methamphetamine Hydrochloride) were found in the killed man's pockets. (Photo by Damir Sagolj/Reuters)

Vivid colors and bizarre shapes come together in a false-color image that could be an illustration for a fantasy story. This labyrinth of exotic features winds its way along the edge of Russia’s Chaunskaya Bay in northeastern Siberia, seen as a vivid blue half-circle at the bottom of the image Two major rivers, the Chaun and Palyavaam, flow into the bay, which in turn opens into the Arctic Ocean. Ribbon lakes and bogs are present throughout the area, created by depressions left by receding glaciers. (Photo by USGS/NASA)