What: Selection of the host city for the 2020 Summer Olympics.

Where: Buenos Aires, Argentina.

Venue: Hilton Hotel.

When: Saturday, Sept. 7.

The Candidates: Istanbul, Madrid and Tokyo.

Who Decides: The International Olympic Committee.

The Meeting: 125th IOC Session.

The Vote: IOC members will vote by secret ballot until one city receives a simple majority. The city receiving fewest votes is eliminated after each round. The maximum number of rounds is two.

How Many: The IOC has 103 members. President Jacques Rogge has chosen not to vote, and members from the three bid countries don’t vote while their city is still in contention. Spain has three IOC members, Japan and Turkey have one each.

First Round: If all members attend, 97 will be eligible to vote, meaning 49 votes are needed for victory. If the election goes to the second round, member or members from the country eliminated in the first ballot can vote in the second round.

Presentations: Each city will make 45-minute final presentations, with an additional 15 minutes for questions and answers.

The Order: Istanbul, Tokyo and Madrid.

The Ballot: Voting will begin at 12:45 p.m.

The Announcement: The ceremony will begin at 2 p.m. Rogge will open the sealed envelope and announce the winner.

Associated Press