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.

Buildings are seen near the ocean as reports indicate that Miami-Dade County in the future could be one of the most susceptible places when it comes to rising water levels due to global warming on March 14, 2012 in North Miami, Florida. Some cities in the South Florida area are starting to plan for what may be a catastrophic event for the people living within the flooding area. (Photo by Joe Raedle/Getty Images)

Krastsvetmet, located beside the beautiful Yensei river in the metropolis of Krasnoyarsk, Russia, is a refinery of all types of precious metals on an industrial scale.

Pedestrians and traffic cross Tower Bridge as viewed through a glass viewing platform on the high-level Walkways during a preview to launch the new viewing experience at the Tower Bridge Exhibition centre in London on November 10, 2014. The new glass flooring at the Tower Bridge Exhibition 42 metres above the river Thames will allow visitors to gaze down on the bridge and river and allow them to experience the bridge opening from above. (Photo by Andrew Cowie/AFP Photo)

Astronaut Chris Hadfield Explains How to Wash your Hands in Space.

Surfer Arlen Macpherson sits on his board, which has an electronic shark repellent device installed, at Sydney's Bondi Beach in Australia, August 18, 2015. A spate of shark attacks in Australia has left some of world's top surfing beaches deserted and many people having second thoughts about taking a swim as the summer approaches. Macpherson paid A$390 for a device embedded in his surf board to repel sharks by emitting an electronic force field that overpowers its sensing organs. (Photo by David Gray/Reuters)

At this year’s Venice Bienniale in Italy, the Korean pavilion has a curious exhibit called “Commissions for Utopia”. It includes renderings from North Korea’s top architects and artists (all anonymous), many of whom studied at the Paekho Institute of Architecture, North Korea’s state-run architectural college, and none of whom have ever left the country. They were asked to create a vision of North Korea’s future sustainable architecture for its expanding tourism industry. Their final products are a glimpse into what it would be like to envision the future after being entirely cut off from the present for almost 70 years. (Photo by Nick Bonner/Kyle Vanhemert/Venice Architecture Biennale)