Facing high winds and cold, competitors were assembling for the start of the TCS New York City Marathon Sunday morning.

The National Weather Service issued a wind advisory for New York City until 6 p.m. and with the chill of the north wind, the temperature just before the start of the race was about 36 degrees.

There was also heightened security, and at some point in the race, the one-millionth runner in the history of the marathon will cross the finish line.

"I'm kind of amazed that there's been a million situations where someone ran 26-plus miles, so that is a testament to the human spirit," Mayor Bill de Blasio said Thursday at a Manhattan event previewing the festivities.

He called the event the pride of the city.

"We're New Yorkers, so from time to time we brag about the fact that the things we have are the biggest and the best," he said. "This is a case where no one debates: We have the biggest and the best marathon anywhere in the world."

More than 50,000 runners, wheelchair and handcycle athletes will wind their way from the starting line in Staten Island through Brooklyn, Queens and the Bronx toward the finish line in Manhattan's Central Park. Hundreds of thousands of spectators will cheer them on along the route.

NYPD Commissioner William Bratton on Thursday touted the marathon, which had its first running in 1970, as a tradition in the city and joked it was a rare "26 miles without a red light."

Bratton said more than 4,000 city police officers will provide crowd and traffic control. There also will be surveillance from the air by four blimps, from the waterways by 20 vessels, and by counterterrorism and FBI teams around the city. Bratton stressed that no direct threat had been made against the race, but all precautions are being taken for a "safe, happy and memorable" event.

Marathon stars, including Olympian Meb Keflezighi, victor of the 2009 New York City Marathon and the 2014 Boston Marathon, said participating and feeling a sense of unity with the city is as important as winning the race.

"You have to perform. You have to persevere," Keflezighi said Thursday. "You start together and you finish, and everybody feels a great sense of accomplishment."

Paralympian and wheelchair racer Tatyana McFadden, who has won the New York City, Boston, Chicago and London marathons, said the event brings "all walks of life together at the starting line."

The marathon comes after a month during which soldiers in Canada were attacked by lone-wolf, terrorism-linked assailants and two NYPD officers in Queens were injured by what Bratton described as a "self-radicalized" man wielding a hatchet. Additionally, security was ramped up in the city after President Barack Obama in September launched an air offensive against Islamic State extremists in the Middle East.

Bratton and de Blasio said the best way to deter attacks is for the police and the public to stay alert.

"I want people to recognize that we are never powerless in these situations," de Blasio said. "We may know something. You may see something that could help the NYPD do its job."