Canoeists are framed by the tail of a breaching whale in Antarctica in April 2023. The photographer, from California, writes: “It was probably a once-in-a-lifetime moment”. (Photo by Jiahong Zeng/Solent News)

Judges watch athletes during the women's individual compact NH 5km competition at the Nordic Combined World Cup in Ramsau, Austria, Saturday, December 16, 2023. (Photo by Matthias Schrader/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.

Camera trapper Xavier Hubert-Brierre put this large mirror on the side of a road through the jungle in Gabon and left a camera there to record how the animals would respond to their own reflections. A silverback gorilla thought it was seeing another silverback and responded by trying to scare off the potential challenger… (Photo by Xavier Hubert-Brierre/Johns Hopkins University Press)

A team from Woody's Ice Cream shop wrangle a large inflatable dinosaur down the street during the Independence Day Parade in Fairfax, Virginia July 4, 2015. Americans marched in star-spangled parades, ran relay races, gathered for fireworks shows and crowned a new world hot dog eating champion as they celebrated Independence Day in traditional style on Saturday. (Photo by Jonathan Ernst/Reuters)

Second placed Kalex Moto2 Tito Rabat (rear R) of Spain and third placed Kalex Moto2 Alex Rins of Spain spray with champagne during the award ceremony for the Czech Grand Prix in Brno, Czech Republic, August 16, 2015. (Photo by David W. Cerny/Reuters)

Alessandra Perilli, of San Marino, competes during the trap women's qualification at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, August 7, 2016. (Photo by Hassan Ammar/AP Photo)

A fan of Japan reacts after Crotia winning the penalty shoot out during the FIFA World Cup Qatar 2022 Round of 16 match between Japan and Croatia at Al Janoub Stadium on December 5, 2022 in Al Wakrah, Qatar. (Photo by John Sibley/Reuters)