(CNN) Throngs of revelers packed cities around the globe to usher in 2018 with public celebrations and fireworks, despite fears of terrorism and frigid weather in some places.

In New York, hundreds of thousands of people packed Times Square in the 9-degree Fahrenheit weather, with a wind chill of 4 degrees below zero, to watch the 2018 ball drop and confetti rain down on the street. The frigid temperature made it the second coldest New Year's Eve ball drop on record in New York. The coldest ball drop still holds at 1-degree Fahrenheit in 1917.

Law enforcement agencies had added additional security measures, including extra checkpoints, police dogs, street closures and undercover officers.

"You will see a stronger police presence out there than we've seen, even than what we've seen in recent years. And that's prudent, given the terror events we have seen and studied around the world as well as the three incidents here in New York over the past 15 months," said NYPD Commissioner James O'Neill before the East Coast clock struck midnight.

And in Las Vegas, where a gunman killed 58 people at a music festival in October, officials installed extra security -- including National Guard officers and snipers on rooftops -- along the famed Las Vegas Strip. Fireworks lit the sky in a synchronized spectacle over the city as the new year began.

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