[1] The fall 2009 G20 summit was held at the David L. Lawrence Convention Center in Pittsburgh, Pennsylvania, United States, on September 24–25, 2009.

[4] The primary venue of the summit was the David L. Lawrence Convention Center, which was at one point the largest Leadership in Energy and Environmental Design-certified building in the world.

[6] Other venues used around the city include The Andy Warhol Museum, the Pittsburgh High School for the Creative and Performing Arts and Rosemont, the working farm of Teresa Heinz Kerry.

Pittsburgh Mayor Luke Ravenstahl also attempted to alleviate problems by meeting beforehand with some of the groups expected to protest during the event.

[8] Chinook and Black Hawk helicopters, armored Humvees and crews of U.S. Army soldiers, as well as 10 25-foot boats with M240 machine guns from the Coast Guard, were on hand in the event of large-scale violent protests or a terrorist attack.

The Peoples' Summit included outright opponents of the G20 (such as radical historian Howard Zinn, who addressed the gathering via special video) as well as some who hoped to influence it in what they considered to be "progressive" directions.

Their outstanding efforts are certain to create a greater understanding about the challenges we face, the solutions we should explore and the social dialogue that is necessary for the realization of a better world.

[42] At around 10:15 a.m. on Wednesday, September 23, Greenpeace activists hung a banner, warning of the dangers of increased CO2 emissions, from the deck of the West End Bridge facing downtown Pittsburgh over the Ohio River.

On Thursday, September 24, the Pittsburgh G20 Resistance Project held a march and a day of direct action at Arsenal Park in the city's Lawrenceville neighborhood.

Police fired pepper spray at a crowd of an estimated 500 demonstrators to disperse a protest march a few hours before the start of the Summit.

Hundreds of police swarmed and encircled the peaceful crowd, which spilled over onto Forbes Avenue and Bigelow Boulevard near the Cathedral of Learning.

[46] An estimated 300 riot police lined the sidewalk behind the William Pitt Union, with 200 more officers blocking Forbes Avenue nearby to contain the protesters.

The Pittsburgh G20 Resistance Project called for "Everywhere Protests" at various locations and businesses (mostly banks and large corporations) throughout the city Friday morning (September 25).

The demonstration was quite diverse, including religious and community activists, anarchists, socialists, environmentalists, human rights advocates, opponents of war, trade unionists, veterans, and others.

Taking place in Schenley Plaza and at the nearby University of Pittsburgh campus, they involved more sweeping arrests, and more charges of police violence, than had been the case the night before.

[55] New York City activist Elliott "Smokey" Madison used Twitter to report an order to disperse message from the Pittsburgh police during the protests.