Barack Obama played to the biggest crowd of his campaign thus far, in his visit to Philadelphia, just days ahead of the crucial Pennsylvania Primary.
Over 35,000 people turned out to hear Obama speak at the Independence Visitor Center, a number which far exceeded the 30,000 who came to him and Oprah Winfrey in December in South Carolina.
Polls have shown Obama closing on Hillary Clinton, even after the much publicised bitter comments by Obama last week, and the tough debate conducted by ABC.
Obama spent at least some of his speech on Hillary Clinton, effectively labelling her a political opportunist.
"She's taken more money from Washington lobbyists than any other candidate in this race, even John McCain, because she says that lobbyists represent real Americans" he said. "She's taken a different position at different times on issues as fundamental as trade and even war, to suit the politics of the moment."
Obama as a contrast said that he was focusing clearly on change politics, and was not "running for President to play the same old Washington game.I'm running to end the game-playing" he said.