3.5 years
The Expos played in Olympic Stadium from 1977-2004 and Jarry Park from 1969-1976. For the final two years of the team's existence (2003 and 2004), MLB had them play 22 'home' games per season at Hiram Bithorn Stadium in San Juan, Puerto Rico.
The olympic city and stadium have to be built , and it takes roughly four years to complete.
About 2 years.
2 Years
The opening and closing ceremonies, along with athletics and football, will be held at the National Stadium in Beijing. Click on the 'National Stadium' link below to see pictures of it.
It takes 7 years to prepare for an Olympic game so they're probably getting ready for their turn ( i think)
3 years
For the London Olympiad, the land preparation for the stadium began in mid-2007, (with the official construction start date on 22 May 2008) and construction took four years (to 2011) to complete.
the olympics are very competitive this year
Historically, it has taken anywhere from 2-6 years to do.
When they decide to build one. Well, actually, it would probably be a couple of years after they decide to build one, since they'll actually have to build it.