Who: Leaders from the 19 leading industrial nations and the European Union representing 85 percent of the world's economy. Many leaders were already in the U.S. for the U.N. General Assembly meeting in New York, so President Barack Obama offered to host the meeting, White House spokesman Robert Gibbs said back in May.

What: A two day conference

When: September 24-25

Where: David L. Lawrence Convention Center in downtown Pittsburgh, Pennsylvania. The city was chosen because it  has had its share of economic troubles but because  of foresight and investment is now renewed, Gibbs said. He added that President Obama believes it would be a good place to highlight that.

Why: According to the U.S. State Department: At the Pittsburgh G-20 Summit, leaders will review the progress made since the Washington and London Summits and discuss further actions to assure a sound and sustainable recovery from the global financial and economic crisis.