A security exercise takes place along the River Thames on January 19, 2012 in London, England. The exercise including around 44 police officers, 94 military personnel, 15 boats and a Royal Navy Lynx helicopter was conducted by both the Metropolitan Police and the Royal Marines and designed to test their joint capability ahead of the 2012 London Olympic Games. (Photo by Dan Kitwood/Getty Images)

Built for over a million people, the city of Ordos was designed to be the crowning glory of Inner Mongolia. Doomed to incompletion however, this futuristic metropolis now rises empty out of the deserts of northern China. Only 2% of its buildings were ever filled; the rest has largely been left to decay, abandoned mid-construction, earning Ordos the title of China's Ghost City.

The Democratic Republic of the Congo’s misfortunes have often eclipsed its good news, with ongoing armed conflicts and most recently an Ebola outbreak. Much of the world knows little of the country’s vibrant arts scene, and last weekend in the capital, Kinshasa, models showed off daring new looks dreamed up by local designers on the catwalk. (Photo by Olivia Acland/The Guardian)

“Julien Mauve is a Paris based professional web designer, front-end developer and content manager who loves innovation, experimentation and creation. Julien has taken up photography as a hobby. His collection Back to Childhood is all about bringing the long lost memories of early days into the adult life. How he came about that idea? Julien stumbled upon some of his old toys in his grandpa’s attic and felt a connection to every single one of them. Each toy brought back a fond memory”.

A camel foams at the mouth as he is whipped by a robot jockey during a race at Nad al-Sheba on December 6, 2006 in Dubai, United Arab Emirates. This is the first season that robotic jockeys have been used to race camels in Dubai. Controversially children from India were used to ride the camels in past seasons. These robot jockeys costing 15000GBP and up, were designed in Geneva and include shock absorbers and GPS tracking systems. The camel's owners control them from their speeding four wheel drives at the side of the track. (Photo by Chris Jackson/Getty Images)

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.