"Violence is no answer - we must be the antidote to violence. We must go another way," said Rev. Jesse Jackson. "Stop the violence now - give peace a chance."
Jackson encouraged protesters to keep the peace during his speech at the Petrillo Band Shell. He was one of several speakers to take the stage before the massive march began.
A sea of protesters snaked through the Loop, eventually marching down Michigan Avenue. Police officers in riot gear lined both sides of the streets.
The march ended at Michigan and Cermak where another rally was held. Several veterans of Iraq and Afghanistan symbolically gave back the medals they had received for service to NATO.
There was a lot of negotiation that led to the vets not just leading a parade of many different causes but also being the only ones allowed to speak at parade's end.
Their message, at least initially, got lost in a scuffle because it preceded the clash between police and protestors. Nonetheless, it was a quite powerful message.
Each of them, for their own reasons, concluded that the wars they fought in were wrong, and so they marched together today, about four dozen veterans of the wars in Iraq and Afghanistan, each prepared to return their Global War on Terror medals in symbolic protest. Soldiers like Sgt. Jacob George, who did three tours in Afghanistan.
"I do not feel like the intentions of the overall mission matched my intentions as an individual and most of the people who served," said George. "I am willing to give them back even though it is a very emotional thing for me."
"I was in Iraq in '03 and what I saw there crushed me," said Ash Wilson. "I don't want us to suffer this again, and I don't want our children to suffer this again. So I'm giving these [medals] back."
One by one, 45 veterans spoke of their own anger or pain, and each turned and threw their medals toward McCormick Place. They had asked that the NATO representative formally accept them. That did not happen.
"I'm one of 40,000 people that left the United States Armed Forces because this is a lie," said one veteran.
"I will not continue to trade my humanity for false heroism," said another.
Vincent Emanuele is from a multi-generational military family. Returning his medals, he says, is about sending a message to the world, but is also cathartic.
"For many veterans to deal internally with what it is we have experienced overseas and then to come back and to make amends for ourselves," said Emanuele.
"This medal right here is because I'm sorry - I'm sorry to all of you," said Aaron Hughes. Hughes, who served in Iraq, helped organize what became a moment on an international stage - a moment meant, he says to show disdain toward policymakers and not the men and women still fighting.
"I love all my brothers and sisters that are in Afghanistan still, and I hope they get to come home soon," said Hughes.
The NATO leaders were meeting just a couple blocks from where the military marchers spoke their peace and threw their medals. We don't know if the event made it to their attention.
The ex-servicemen and women who took part say they - through this gesture - wanted to send a message - that withdrawal from Afghanistan cannot come too soon, and that the men and women returning are not getting the care - specifically, the mental health care, they need.
The ceremony was reminiscent of a similar scene at the U.S. Capitol decades ago when Vietnam War veterans threw their medals over a barricade because they were not allowed in.