The long-awaited G-20 Summit gets under way this week as Pittsburgh opens its doors to leaders from 20 of the world’s largest economic powers, along with the legions of protesters who come with them. As the summit began, protestors marched toward the city center and soon clashed with police, who fired pepper spray and rubbert bullets into the crowd. The protesters clogged streets, banged on drums and chanted. For more, we speak to Mackenzie Carpenter, reporter for the Pittsburgh Post-Gazette.