The three candidates still standing to win the right to host the 2020 Olympics all acknowledge that they have a tough task to emulate the Games hosted so successfully by London this year.

Delegations from the Istanbul, Madrid and Tokyo bids were all in London and the appraisal of International Olympic Committee (IOC) President Jacques Rogge at the closing ceremony will still be ringing in their ears.

"These were happy and glorious Games," said the 70-year-old Belgian.

Buenos Aires will be a momentous time for not only the three bid cities, who will learn their fate when the 100+ IOC members vote there on September 7, but also for Rogge, as he will step down after 12 generally highly successful years.

All of the cities enter 2013 eyeing the finishing straight with reason to be optimistic.

Istanbul believe that they can prevail at the fifth attempt -- though this is the first realistic chance they have had of winning -- with the government wanting to prioritise the Olympics rather than a bid for the Euro 2020 football championships.

Rogge had emphasised that IOC rules did not allow another major sporting event to be held in the country of the host city in the same year.

The Istanbul bid chief, former basketball player turned successful businessman, Hasan Arat told AFP that the IOC would be making an historic decision by giving them the Games.

"My dream is to make Olympic history, to really catch an historic moment - one city, one Games and two continents.

"The athletes will have the unique experience of sleeping on the European continent and competing on the Asian continent."

Tokyo, who are the only one of the trio to have previously hosted the Games (1964), also are looking to tug at the IOC heartstrings and persuade them the perfect panacea for the 2011 tsunami that devastated the country would be the Games.

"The bid process - and ultimately having the chance to host the Games - is helping Japan heal and re-unite after a difficult 2011," bid chief Tsunekazu Takeda told AFP.

"Without a doubt, Tohoku (the region affected by the tsunami), and the rest of Japan, will benefit from the Games."

Madrid too can dream of securing the Games, after finishing surprise runners-up behind Rio de Janeiro for the 2016 edition, especially as despite Spain's severe economic crisis they made the short list, easily seeing off Doha.

It was the second successive time Doha flopped in their efforts to make the short list and serious questions will be asked why the successful formula that worked on FIFA for winning the race to host the 2022 World Cup falls well short when their message gets to be put across to IOC members.

While there are no officially declared candidates to succeed Rogge, it is generally accepted German lawyer and former team fencing Olympic gold medalist Thomas Bach will throw his hat into the ring.

However, while many have seen him as the Crown Prince, there may be a wish to take the presidency away from European hands after the last three supremos have been from the 'old continent'.

Indeed, only one non-European has held the position, the unloved American Avery Brundage.

Puerto Rican banker Richard Carrion is prominent in some lists and won respect for his handling of the television broadcast rights negotiations with NBC.

One seen as a possible compromise candidate is the impressive Taiwanese architect, and president of the International Boxing Association (AIBA), Dr Ching-Kuo Wu.

But his age may count against him as he will be nearly 67 by the time of the election.

Rogge for his part, as he told AFP in May, will retire gracefully and is just looking forward to reading, visiting art galleries and driving his grandchildren around.

"Normally with regards to legacy you only speak about that when people die," he said.

"I didn't take the mandate up to leave a legacy and historians can write about that in 20 years time if they so wish. However... I took up the baton of (Juan Antonio) Samaranch and I believe I will leave behind some notable successes."