A young woman cools herself in a fountain in Budapest, Hungary July 6, 2015. Over the weekend, a heat wave has reached Hungary with temperatures topping 38 degrees Celsius (100.4 degrees Fahrenheit). (Photo by Laszlo Balogh/Reuters)

A fisherman carries a large Pirarucu (Arapaima gigas) at the Piagacu-Purus Sustainable Development Reserve in Amazonas state, Brazil, on October 24, 2019. The pirarucu -a giant fish of the Amazon, that had been on the verge of extinction- can measure up to three meters and weigh more than 200 kilos. The soft and tasty white meat fish is nowadays served in renowned restaurants in Rio de Janeiro. (Photo by Ricardo Oliveira/AFP Photo)

The Pioneer Team, a civil aerobatic team from Italy, let off pyrotechnics from their Pioneer 330 aircraft during the Malta International Airshow off SmartCity Malta, outside Valletta, Malta, September 24, 2016. (Photo by Darrin Zammit Lupi/Reuters)

Cheng Chen (R), a 27-year-old worker at a state-owned enterprise, poses for a photograph with his nephew who is wearing his home-made Iron Man armour, in Xuzhou, Jiangsu province April 13, 2015. It cost Cheng about 500 yuan ($81 USD) to make the armour, which weighs about 4 kilograms, with plastic boards and LED lights, local media reported. (Photo by Reuters/Stringer)

Actress Kerry Washington, Harvard University's Hasty Pudding Theatricals' Woman of the Year, throws wine in the face of an actor playing Republican presidential candidate Donald Trump, Thursday, January 28, 2016, as she is roasted in Cambridge, Mass. (Photo by Elise Amendola/AP Photo)

The Founders' Award winner, Downey Rose Float Association “Exploring the Everglades” float, moves through 127th Rose Parade in Pasadena, California January 1, 2016. (Photo by David McNew/Reuters)

Models on the catwalk Yeezy: Season 4 show, Spring Summer 2017, New York Fashion Week, USA on September 7, 2016. (Photo by Your Name/BFA/Rex Features/Shutterstock)

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)