Shooting star by Tony Wu, US/Japan. Winner, underwater. The electrifying reproductive dance of a giant sea star. As the surrounding water filled with sperm and eggs from spawning sea stars, Wu faced several challenges. Stuck in a small, enclosed bay with only a macro lens for photographing small subjects, he backed up to squeeze the undulating sea star into his field of view. The dancing posture of spawning sea stars rising and swaying may help release eggs and sperm, or may help sweep the eggs and sperm into the currents where they fertilise together in the water. Kinko Bay, Japan. (Photo by Tony Wu/Wildlife Photographer of the Year)

Britain Horse Racing, Royal Ascot, Ascot Racecourse on June 17, 2016. Chelsea pensioners with a racegoer posing between them. (Photo by Toby Melville/Reuters/Livepic)

“In the late afternoon after a rain, genji botaru fireflies (luciola cruciate) dance above the swollen creek. The rocks darkened by the rain reflecting the blue sky, and the yellow-green ribbon of the glow from the fireflies, make a beautiful contrast”. – Takehito Miyatake. (Photo by Takehito Miyatake/Steven Kasher Gallery)

Indonesian residents look at the Mount Sinabung volcano as it spews volcanic ash near the Tiga Pancur village in Karo, North Sumatra on August 3, 2016. Volcanic eruptions in Indonesia in recent days have forced the closure of two airports and disrupted some flights to the holiday island of Bali, officials said August 3. Mount Sinabung, a volcano on the western island of Sumatra which has been rumbling for some time, also erupted violently on August 2, although its ash clouds did not disrupt any flights. (Photo by Y.T. Haryono/AFP Photo)

Arsenal football supporters cheering from the train carriage window as they leave Euston Station, London, on their way to Birmingham for their team's match against Aston Villa which they lost 3-5. (Photo by Douglas Miller/Topical Press Agency/Getty Images). 19th November 1932

Battersea Power Station. The chimney rims are thinner on top than you might expect. (Photo by Bradley L. Garrett)

Australian cosplay enthusiast Sunni Daniele dressed up as his favourite character from either animation, comic or video game poses for a photograph during Oz Comic Con in Sydney, Australia, 27 September 2015. Cosplay is a combination of the words 'costume' and 'play' where fans dress up as their favourite Japanese comic characters. (Photo by Dan Himbrechts/EPA)

Horse riders perform with guns during the El-Jadida International Horse Show in El-Jadida, south of Casablanca, Morocco, October 15, 2016. (Photo by Youssef Boudlal/Reuters)