New York - New Yorkers on Tuesday began the process of replacing the billionaire mayor who has led their city for 12 years.
Mayor Michael Bloomberg took office shortly after the terrorist attacks of 11 September 2001 and continued the city's transformation as one where murders have dropped, but the divide between rich and poor has grown.
The front-runner to replace Bloomberg, Bill de Blasio, has focused on that divide and promoted himself as the cleanest break with the current administration.
If he gets more than 40% of the vote on Tuesday, he would avoid a second election among the top two finishers in his political party 1 October.
In a Quinnipiac University poll released on Monday, de Blasio was the choice of 39% of likely Democratic voters.
De Blasio's rise was unexpected. He placed his interracial family at the heart of his campaign.
City Council Speaker Christine Quinn, who is trying to become the city's first female and first openly gay mayor, led the polls for most of the year but has seen support disappear as her rivals linked her to the bitter debate to let Bloomberg run for a third term in 2009.
The city comptroller, John Liu, is trying to become the city's first Asian-American mayor but has been hurt by a fundraising scandal.
Anthony Weiner jolted the race in May when he returned to politics after resigning from Congress in 2011 after sending lewd online messages to women who were not his wife, a well-known aide to former US Secretary of State Hillary Rodham Clinton.
Weiner led the polls for mayor for nearly a month - until it was revealed that he had continued to send the explicit messages after leaving office.
Republicans will look to continue an improbable winning streak. Though outnumbered by Democrats in the city 6-to-1, the party has won the last five mayoral elections.