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)

The hard-worked hands of Jacaba Coaquira, 80, holding the green beans she grew on her land. This year the production of her land was affected by lack of rain and early cold weather that froze the crops before they finished growing. Santiago de Okola, Bolivia. (Photo by Renée C. Byer/Living on a Dollar a Day)

Police haul a youth to the paddy wagon as an undetermined number of arrest were made in downtown Atlanta, Georgia, February 25, 1971, as police moved in to disperse black youths after windows were broken and rocks and fruit thrown in what officers called “a major disturbance”. (Photo by Charles Kelly/AP Photo)

Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

Aerial photo taken on April 10, 2022 shows the construction site of Haikou duty-free shopping complex in Haikou, south China's Hainan Province. With a total construction area of about 926,000 square meters, the Haikou duty-free shopping complex project is expected to be officially put into use this year. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

An employee of a bakery talks on his mobile while balancing on his head a tray of freshly baked bread from a local bakery in a street in Cairo, Egypt, January 12, 2016. (Photo by Asmaa Waguih/Reuters)

In this November 21, 2015 photo, Camila Lopez Rivas, 14, poses for portraits on a beach in Havana, Cuba, as an assistant lifts the train of her dress to make it look like its flying in the wind. Camila lives in Miami, the daughter of a truck driver who left Cuba when she was a baby. She doesn't remember the island, but wanted to return for the photographs and videos that Latin American girls typically take for their 15th birthdays. (Photo by Ramon Espinosa/AP Photo)

Gymnast Ahmad al-Sawas performs gymnastic moves near damaged buildings in the rebel-held Bustan al-Qasr neighbourhood of Aleppo, Syria March 26, 2016. As Syrian gymnast Ahmad al-Sawas watched his country fall apart, his Olympic dream collapsed too. The last national champion before the fighting began, he knew that supporting the anti-government side in the five-year-old civil war would prevent him from being selected for the Rio Games. (Photo by Abdalrhman Ismail/Reuters)