Tensions boiled over as protesters marched to the Vietnam Memorial. When the park closed at 10 p.m., some clashed with the hundreds of police officers, with photographers caught in between.
Police arrested more than 50 demonstrators after a day that saw scuffles and shoving matches on Sixth Avenue.
In the end, the NYPD prevailed, with some people bloodied, others tied up and one left with a shoe print on his head. But for most of the thousands of protesters, it was a peaceful march for a range of issues from the economy to more lofty causes.
The May Day marches caused enormous traffic snarls throughout Manhattan, and one woman said she didn't think their message was worth the cost.
"It's going to cost the city of New York, which is in debt now, millions and millions of dollars in police overtime," she said. "What's the point of that?"
Outside Zuccotti Park Wednesday, there was not a large police presence. The small group of protesters camped out at the group's original home base will be allowed to stay there without any problems.
Earlier Tuesday, activists spread out over the city with Occupy members leading a charge against financial institutions. They faced police lined up in front of Bank of America on West 42nd Street and chanted: "Bank of America, bad for America!"
Julian Kliner, 22, said protesters' main issue with the banking giant is "how many people the Bank of America foreclosed as a result of predatory lending."
Organizers initially called for protesters to block one or more bridges or tunnels, but some protesters said later in the day those plans had been canceled. Occupy activists also had said they planned to bring business to a standstill on May Day. But there was no sign of any major business disruptions. May Day protests also took place Tuesday in Los Angeles, the San Francisco Bay Area, Chicago, Atlanta and other cities.
Letters containing a white powder that appeared to be corn starch were sent to some institutions. Two letters were received Tuesday at News Corp. headquarters - one addressed to the Wall Street Journal - and a third was delivered to Citigroup. Their message said: "Happy May Day."
Seven letters were received Monday at various banks and one was sent to Mayor Michael Bloomberg.
"This is a reminder that you are not in control. Just in case you needed some incentive to stop working," the letters read, according to authorities.
A group also picketed outside New York University to protest the university's expansion plans in Greenwich Village.
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