Barack Obama's rally in Philadelphia on Friday drew an estimated 35,000-40,000 people in Independence Park. Here's the story from the AP:
PHILADELPHIA (AP) - Barack Obama was greeted by the largest crowd of his campaign Friday night in Philadelphia. Some 35,000 people jammed into Independence Park to see the Democratic presidential candidate, four days before this state's crucial April 22 primary.
Frank Friel, director of security at the Independence Visitor Center, made the official estimate.
The crowd exceed the 30,000 who greeted Obama and Oprah Winfrey in December in Columbia, S.C.
Obama told the crowd the United States is at a crucial moment in its history, much like what the founding fathers faced in Philadelphia.
"It was over 200 years ago that a group of patriots gathered in this city to do something that no one in the world believed they could do," Obama said. "After years of a government that didn't listen to them, or speak for them, or represent their hopes and their dreams, a few humble colonists came to Philadelphia to declare their independence from the tyranny of the British throne."
The Illinois senator called Democratic rival Hillary Rodham Clinton a "tenacious" opponent but said it was time to move beyond the politics of the 1990s.
"Her message comes down to this: We can't really change the say-anything, do-anything, special interest-driven game in Washington, so we might as well choose a candidate who really knows how to play it," Obama said.
http://apnews.myway.com/article/20080419/D904LCA01.html
Of course this is expected from an Obama rally. People shouldn't even be surprised by his ability to attract tens of thousands of people. But what was amazing was what happen following the rally. From The Atlantic reporter Marc Ambinder...
PHILADELPHIA -- It wasn't so much that Barack Obama had real fight in him tonight, or that more people attended his rally in front of Independence Hall than any other event since he announced his candidacy. It was the spontaneous demonstration of support that happened when it ended.
5,000 people (at least) had nowhere to go but up Market Street. Obama's charge of the night: "Declare independence!" was with them. They started with the familiar "O-Bam-A." By 7th and Market, they had graduated to "Yes we can!" By 10th and Market, with hundreds streaming in between cars on the road, they were just cheering. At first, a few Philly cops, killjoys, tried to rough the crowd to the sidewalks. It didn't work. The cops retreated to the sidewalks. By the time I ducked into my hotel, a full mile away from Independence Park, the Obama crowd was still marching.

The headlines Obama intended to generate were as follows: first, the secondary point, so reporters can write that Obama looked forward to the general election: John McCain is man who deserves respect. "But the change this country needs will not come rom a third George W. Bush term. And what is exactly what his campaign is offering. John McCain is offering four more years of a war with no exit strategy, a war with no end in sight, a war that is sending our troops on their thid, fourth and fifth tours of duty." Four good measure, Obama repeated the disputable claim that McCain saw "great progress" from seven and a half years of George W. Bush's" economic program.
The main headline was -- is -- a series of non-wimpy, crisply delivered, very direct digs at Hillary Clinton. Obama started this riff, but aware that the crowd was still thinking about McCain, paused, then said,"Listen up you guys."
Quiet.
Hillary Clinton "is a tenacious campaigner and is a committed public servant," he began. (Boos. I mean, Obama could have said the same thing about Brownie.) But her message, he said, is "that we can't really change the say anything, do anything special interest game of so we might as well choose a candidate who knows how to play the game." He mocked her "kitchen sink strategy." Then he said, "I'm not running to be the president who plays the same old game. I'm running to end the game."
"This year we can’t afford the same old politics. This year we can declare our independence from this kind of politics."
The metaphor was labored, but, I mean -- how could you not use it? (To those of us who're watching John Adams on HBO, we can envision George Washington giving his second inaugural addresson on the second floor balcony of Independence Hall -- all of this visible to Obama and to the press, it was -- sorry VandeHarris, a little eerie.)
An Obama aide sized the crowd at about 40,000. It was probably was a little bit less, but a senior campaign official said it was the biggest the campaign had ever seen.
As usual, about 3,000 guests directly in front of Obama were sent through magnetometers and enclosed by metal barriers. Another 25,000 crowded Independence Park; some even listened from a good three thousand feet away, well behind Independence Hall.
I counted at least a hundred Philadelphia police officers. There were state troops. TSA personnel magging the crowd. A helicopter hovered over the square. The fire department set up a command post with extra medical supplies. It was some way to start Obama's final Pennsylvania push.
http://marcambinder.theatlantic.com/archives/2008/04/philly_ignites_for_obama.php
Now this is what I call rabid supporters for Obama. A spontaneous march through Philly for Obama? That's amazing. It is events like this (especially the march) that makes me have hope that Obama can actually win Pennsylvania. Multiple polls have shown a tightening in the race the past few days. And remember, Obama is doing this in a closed primary, meaning only Democrats can vote in Tuesday's state primary. Imagine if this was an open primary? Then there would be no doubt Obama could pull off a victory. Tuesday will be the big day....