The decision not to indict Officer Daniel Pantaleo added to the tensions that have simmered in the city since Garner's death on July 17 death of Garner - a case that sparked outrage and drew comparisons to the fatal police shooting of 18-year-old Michael Brown in Ferguson, Missouri, where demonstrations turned violent and resulted in more than 100 arrests and destruction of 12 commercial buildings by fire.
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Many protesters wanted to head to the tree-lighting ceremony at Rockefeller Center, but couldn't get close because of roadblocks in the area.
Hundreds headed to the West Side Highway at 49th Street where police formed a huge barricade and the highway was shutdown in both direction.
At least 16 demonstrators were arrested at 47th Street and 6th Avenue, some for sitting on the ground, others for trying to get through barricades.
About 35 to 45 protesters lay on the floor of Grand Central Terminal as the evening rush hour got underway. One onlooker spit in their direction. Before leaving, the protesters stood up to chant, "I can't breathe" and "Eric Garner."
In Times Square, a crowd of at least 200 people chanted, "No indictment is denial. We want a public trial" while holding signs that said, "Black lives matter" and "Fellow white people, wake up." Meredith Reitman, a 40-year-old white woman from Queens, held a sign that said, "White silence white consent." She said the decision not to indict shocked her, even though some might think she was being naive to expect an indictment. "We should hope for justice and be surprised every time it doesn't happen," Reitman said.
About 400 protesters began marching through midtown Manhattan, tying up evening rush-hour traffic. Amanda Seales, a 33-year-old black woman from Harlem, said activists needed to get off social media and into the streets. "For black people, this isn't new," she said as she marched. "And this cannot continue."
At 47th and Sixth, police officers tried to keep protesters on the sidewalks. A police loudspeaker warned them that anybody who doesn't leave the street will be arrested.
The Times Square group headed eastbound and the Union Square group northbound, in an attempt to move toward the Rockefeller Center Christmas Tree. Police were ready for that, with a line of interlocked barricades designed to keep them away from the celebration.
The NYPD is expected to bring in more than 1,000 extra officers to keep the situation under control, while officers currently on duty will be asked to work double shifts.
The demonstrations stayed peaceful, a sentiment Mayor Bill de Blasio hoped would persist throughout any such action.
"I believe in the right to peaceful protest as part of a democracy, and anyone who has views as a result of whatever the decision is, if they want to exercise peaceful protest, we welcome that and respect that," he said. "But we also will keep order."
De Blasio also urged protesters to heed the message of Eric Garner's son, Eric Snipes.
"He said that anyone who wants to express themselves to do so peacefully," de Blasio said. "And for his own son, who lost his father, said honor my father by doing any protest in a peaceful manner, I thought it was very powerful. He was not just talking about how you go about making changes and reforms, he was talking about the nature of his own father as a peaceful man, and honoring his memory by being just as peaceful as that man was."
Dave Evans reports on the mayor's reaction to the decision in the Garner case:
The NYPD took to social media and put out a Tweet right after the Garner decision that caused an explosion of tweets criticizing the NYPD. You can see several of them HERE and read MORE.