At the beginning of the 20th century, Edward S. Curtis set out to document what he saw as a disappearing race: the Native American. From 1907 to 1930, Curtis took more than 2,000 photos of 80 tribes stretching from the Great Plains to the Pacific Northwest and Alaska. He then published and sold these photos, along with narrative text, in 20 volumes of work known as “The North American Indian”. It is one of the most significant collections of its kind, “probably the most important photographic document of its age and its topic,” said Jeffrey Garrett, associate university librarian for Special Libraries at Northwestern University. (Photo by Edward S. Curtis)

“APOPO’s Training Center, situated on Sokoine Univeristy of Agriculture (SUA) in Tanzania, was established in 2000 to accommodate training and testing of mine detection rats in near-to-real conditions”. – APOPO

Photo: MDR (Mine Detection Rat) learn to look for mines. (Photo by APOPO's HeroRATs)

Model Kendall Jenner presents a creation during the 2016 Victoria's Secret Fashion Show at the Grand Palais in Paris, France, November 30, 2016. The pulse-quickening, celebrity-filled catwalk event of the year: the Victoria's Secret fashion show takes place in Paris with performances from Lady Gaga and Bruno Mars. (Photo by Charles Platiau/Reuters)

The Olaf balloon glides over Central Park West during the Macy's Thanksgiving Day Parade in New York, Thursday, November 23, 2017. The Macy's Thanksgiving Day parade is the largest parade in the world and has been held since 1924. (Photo by Craig Ruttle/AP Photo)

Participants take part in the annual New Year' s Day Parade in central London, United Kingdom on January 1, 2018. Reports state that 8,000 performers representing the London boroughs and countries from across the globe are parading along the streets of London's West End on New Year’s Day. (Photo by Tolga Akmen/AFP 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.

A prototype of the Space Exploration Technologies Corp. (SpaceX) Starship launch vehicle stands during an event at the SpaceX launch facility in Cameron County, Texas, U.S., on Saturday, September 28, 2019. Elon Musk gave space fans an update Saturday evening on the status of “Starship”, the next-generation vehicle his SpaceX plans to use to eventually take humans to Mars. (Photo by Callaghan O'Hare/Reuters)

North Korean soldiers keep watch at the bank of the Yalu River, near the North Korean town of Sinuiju, opposite Dandong in China's Liaoning province, September 10, 2016. (Photo by Thomas Peter/Reuters)