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)

Participants take part in a New Year's Jump into the Sea in Portoroz , Slovenia, January 1, 2016. (Photo by Srdjan Zivulovic/Reuters)

Hvítserkur is 15 meters high cliff and protrudes out of the sea. The sea erosion has carved holes through its foundations and sculptured it in the unique shape it is today. Some say it is in the shape of a petrified monster.

People play on a beach along the Arabian Sea on a hot summer day in Mumbai, India, April 29, 2016. (Photo by Danish Siddiqui/Reuters)

Waves hit the seawall during heavy seas and high winds in Dawlish in south west Britain, February 2, 2017. (Photo by Toby Melville/Reuters)

Tourists walk as others relax on the beach in the Red Sea resort of Hurghada, Egypt, July 17, 2017. (Photo by Gleb Garanich/Reuters)

Volunteer rescuers prepare to drag a beached humpback calf to sea at Surfers Paradise Beach on August 8, 2011 on the Gold Coast, Australia. The humpback calf was stranded on the beach yesterday for hours before volunteer rescuers were able to drag it back to the sea. SeaWorld Australia says a mother and calf humpback were sighted near where the calf was released and are hoping to get photos to verify it is the same calf and that it has been reunited with it's mother. (Photo by 2011 SeaWorld Australia via Getty Images)