More than a million New Yorkers and tourists in Times Square braved the minus-12 degree Celsius weather to welcome in 2018, just one of the cities worldwide to celebrate New Year's Eve with midnight celebrations.
It was second-coldest New Year's Eve recorded at New York's Times Square, matching 1962. The coldest was in 1917, when it was minus-17.
People gathered more than 12 hours before midnight to count down to midnight, when a giant ball descended from atop One Times Square. Officials said the crowds appeared smaller than many previous New Year's Eve celebrations, most likely because of the cold.
Security was extremely tight throughout Manhattan after a year in which several deadly terror attacks on large crowds took place.
Elsewhere around the world, revelers welcomed 2018 with fireworks, celebrations, and street parties.
Russian had the longest celebration with midnight passing in each of the country’s 11 time zones.
President Vladimir Putin called on Russians to "say the most cherished words to each other, forgive mistakes and resentment, admit love, warm up with care and attention."
Amid intermittent rain in Moscow, fireworks and outdoor gatherings welcomed in the New Year.
Tens of thousands of people converged around Berlin's Brandenburg Gate as Germany ushered in 2018 while fireworks lit up the sky at midnight.
Fireworks also lit up Paris at the Arc De Triomphe as hundreds of thousands of people welcomed the new year along the Champs-Elysees.
Security was high in the French capital after several deadly terror attacks over the past two years, with nearly 100,000 soldiers and police on patrol in popular areas.
A dozen chimes from Big Ben, the bell in the clock tower at the British parliament, greeted 2018 in central London. The clock, which has been shut down for restoration work, was temporarily put back in operation for New Year’s Eve, as it was for Christmas.
One of the first countries to celebrate was Australia, where fireworks exploded over the famed Sydney Opera House to usher in the New Year.
But the very first celebrations were in the Pacific nations of Samoa, Tonga, and Kiribati, where local midnight came at 1000 GMT/UTC on December 31.
Thailand resumed its colorful New Year celebrations as the country ended a year-long mourning period for late King Bhumibol Adulyadej, who died in October 2016.