As Paris and LA are awarded the Olympics, these are the priciest Games on record

Dean Mouhtaropoulos | Getty Images

The International Olympic Committee (IOC) took a "key step" in appointing Paris to host the 2024 Summer Olympic Games Monday after thrashing out a deal between the French capital and rival host Los Angeles.

Los Angeles agreed to delay its aspirations for four years after accepting a $1.8 billion bursary to fund the extended planning period and support youth sports programs.

The agreement brings the two cities ever-closer to their bids of hosting the Games in 2024 and 2028, respectively. If they had not struck a deal, their bids would have gone to a vote by the IOC in Lima, Peru, next month.

If successful, the bids will mark a feat for both cities, which will both become hosts for the third time. However, the Games are not without their controversy, not least due to criticism over exorbitant costs.

Olympic hosts are not required to release official spending figures but researchers from Oxford University Said Business School estimate that Olympic Games since 1960 have cost an average of $4.6 billion, rising to $8.9 billion in the past decade. Here's a look at the most expensive Summer Games, and how much they overran by.

Sydney 2000

The Sydney Harbour Bridge is lit up with Fireworks after the Closing Ceremony of the Sydney 2000 Olympic Games, Sydney Australia.
Adam Pretty | Allsport

At approximately $5 billion, Sydney's millennium games came in above the historical average but well above the eye-watering figures that have come to be the norm over recent years.

Nevertheless, sports-related and infrastructure costs are estimated to have overrun by 90 percent.

The figures bring it in just ahead of Rio 2016, which is estimated to have cost $4.5 billion - a 51 percent overspend. However, the Rio Games were mired in controversy, having taken place as Brazil battles its worst economic and political crisis in almost a century.

Montreal 1976

General view of the Opening Ceremony of the Olympic Games at the Olympic Stadium in Montreal, Canada.
Tony Duffy | Allsport

Montreal's 720 percent cost overrun is the largest recorded and almost three-times that of the second-largest overspend.

Costing $6 billion in the mid-1970s, the Games were seen by many as a financial disaster which weighed on the economy for decades and arguably stunted growth. However, others point to a number of other political, socio-cultural and economic shifts which occurred at the time to damage the city's relative importance.

Beijing 2008

Fireworks light up the sky as paramilitary policemen stand guard during the Opening Ceremony for the Beijing 2008 Olympic Games on August 8, 2008 in Beijing, China.
China Photos | Getty Images

The research suggests that the cost of Beijing's 2008 Summer Games came in at $6.8 billion, just 2 percent over budget.

But, the Games also attracted criticism for their environmental impact as well as over allegations of residential displacement and human rights violations.

Barcelona 1992

Martín Lopez-Zubero of Spain swims in the Men's 200 metres Individual Medley during the XXV Summer Olympic Games on 31 July 1992
Bob Martin | Getty Images

Barcelona's 1992 Olympic Games cost an estimated $9.6 billion. A 266 percent overspend makes it the second most expensive Summer Games on record.

"All Games come in over budget," said Professor Bent Flyvbjerg, who co-penned the study. "If you wanted to make it as difficult as possible to deliver a megaproject on budget, you would do exactly what they do at the Games.

"You would assemble a team that has never delivered this type of project before, in a location that has never seen such a project. Then you would enforce a non-transparent and highly questionable bid process that encourages overbidding and places no responsibility for costs with the entity that decides who wins the bid. That, unfortunately, is the reality we see with the Games."

London 2012

Fireworks ignite over the Olympic Stadium during the Opening Ceremony for the London 2012 Olympic Games on July 27, 2012 at Olympic Park in London, England.
Jamie Squire | Getty Images

At an estimated $14.9 billion, London's 2012 Olympic Games emerged as the most expensive of all time.

Though shy of Sochi's $22 billion Winter Olympics spend, the cost of the project ran over by 100 percent and critics continue to question the long-term impacts it has had on the surrounding area, one of the most deprived parts of the country.

"In 2005, London secured the bid with a cost estimate that two years later proved inadequate and was revised upwards around 100 percent. When it was revealed that the final costs were slightly below the revised budget, the organizers falsely, but very publicly, claimed that the Games were under budget," Flyvbjerg noted.

"Such misinformation is unethical in our view. Our study shows that we should not count on organizers and governments to provide us with reliable information about the real costs of hosting the Olympics."

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