People in City Hall Square cheer Green Party presidential candidate Jill Stein as she addresses the crowd.
Philadelphia CNN  — 

The quadrennial national political conventions are tightly scripted affairs designed to sell the voting public on an idealized version of the party and its candidates for high office. In Philadelphia this week, Democrats are seeking – with varying success – to present a vision of unity behind Hillary Clinton, who will accept the party’s presidential nomination on Thursday night.

But outside, under a wicked hot sun and at least two torrential downpours that sent protesters scurrying under a highway overpass for shelter – the scene has been much different. Activists have launched a series of nonviolent demonstrations while Bernie Sanders bitter-enders have raged against an establishment many believe actively sought to undermine his candidacy.

Mixed into this sweet and sour brew are the carnival barkers, the mystics and zealots, all joined here for this uniquely American event.

On Broad Street, just outside the convention's heavily securitized perimeter, members of "Black Guns Matter," an activist group dedicated to firearm safety, argue with a Trump supporter.  Protesters in Philadelphia, like Cleveland, are not monolithic and have argued as passionately with one another as the few delegates they have been able to confront in the flesh.
Many protesters have sought leafy relief from the scalding sun in FDR Park, the most heavily trafficked protest location. Protesters at these makeshift campgrounds, many of them dedicated Sanders supporters, spent hours making new signs on Wednesday -- this time, for Jill Stein. The Green Party candidate has moved among the demonstrations, seeking to pick up Sanders' mantle as the progressive alternative to Clinton.
Stein was the star speaker at a rally outside City Hall, where she bathed in chants of "Jill not Hill" and congratulated the boisterous crowd for "saying no to that zombie political party whose days are numbered while ours are just beginning."
Her campaign has signs and T-shirts appealing to disaffected Democrats by asking them to "reject the 'lesser evil' and stand up for the greater good."
Most Clinton delegates have steered clear of the protest scene, but this young woman, a DNC volunteer, made her candidate's case. Polls show that an overwhelming majority of Sanders primary backers intend to cast their votes to Clinton on Election Day, but those moderates have been hard to come by on the streets outside the convention. The release of hacked emails from the Democratic National Committee stoked anger among hardcore Sanders supporters, who have long held that their man never got a fair shake.
 After staging a walkout on Tuesday following the roll call vote that officially nominated Clinton, dozens of Sanders delegates walked out of the arena and into the media tent for a silent sit-in. A day later, a dozen of them came together in FDR Park to speak to other Sanders supporters about what to do next. 
The gathering quickly turned into a kind of group therapy session as they discussed their hurt and frustration at both the outcome of the primary and how it was managed by what they regard as a deeply corrupt party establishment.
Khalid Kamau, a Sanders delegate and activist from Georgia, said Sanders inspired him to become a field organizer for the Democratic Party.
"Like everybody else here, I walked out on Tuesday," he said. "Now I'm trying to figure out if I'm going to walk back in."
Trump supporters have mostly stayed away from Philadelphia this week, but there have been the odd exceptions. When they do pop up, reporters and detractors usually flock their way. But as the convention comes to a close, it takes a little more to get the crowds excited.
Less than 100 feet from protests that saw seven people arrested by the Secret Service for breaching a security fence late Wednesday, a group of anti-Israel Orthodox Jews held a mostly quiet demonstration. Some carried Palestinian flags while other handed out pamphlets to curious passersby. The name of the group, "Neturei Karta," translates from Aramaic to "Guardians of the City."
After a group of anarchists managed to crash a fence near a Secret Service checkpoint, which led to a brief shoving match with police, other protesters formed a perimeter around the scene. Demonstrators chanted, "We are nonviolent," and sat down in front of them before deciding to pick up and march north on Broad Street, where a minor dance party broke out.
Sanders remains a popular figure with the progressive left, but many protesters in Philadelphia said they were ready to move on from his campaign and focus on the movement it elevated. For some, that means going to work for Jill Stein. For others, it means organizing around efforts to pressure Clinton and the Democrats to acknowledge their voices and adopt the policies they have spent the past year or more working to advance.

CNN’s Gregory Krieg and Magnum photographer Peter van Agtmael went into the crowds of Philadelphia and Cleveland to get a handle on what it’s like away from the politicians and delegates at the conventions.