Some 6,000 police officers will watch over revellers in Times Square on New Year's Eve as cities across the world beef up security in the wake of the deadly terror attacks in Paris and California.
The up to one million party-goers in New York City can expect to see thousands of officers on patrol in the area, as well as traffic agents, bomb-sniffing dogs and police on horseback, in helicopters and on police boats.
A new unit - 500 police officers chosen and trained to work full time on counter-terrorism - will also be deployed for the first time.
"There will be a tremendous number of officers who you will see, there will be many officers you won't see," New York Mayor Bill de Blasio said on Tuesday as the authorities detailed security preparations.
"We are the best-prepared city in the country, the best-prepared city to prevent terrorism and to deal with any event that could occur."
The unprecedented show of force at one of the world's most well- known countdown events is being matched at similar parties around the world.
In London, for instance, there will be 3,000 Metropolitan Police officers stationed at key locations around the city, with another 3,000 deployed to outer boroughs. Reports also indicated that a further 650 officers from the British Transport Office - some armed - will be at public transport hubs.
Superintendent Jo Edwards, a spokesman for the Metropolitan Police, told the Guardian: "In the UK, the police are operating at the general threat level of severe and we keep our plans under constant review. We feel confidence in our policing operation in terms of safety security and reassurance."
In Paris, celebrations are expected to be muted. France has been in a state of emergency since the attacks last month and large-scale gatherings are officially banned. A planned fireworks show has been cancelled.
In Moscow, the Russian government has taken the rare step of shutting down the Red Square for a private event. It will turn away members of the public from what is a traditional gathering place for those looking to ring in the new year.
Although the authorities in the United States, Britain and France say they have not encountered any credible threats as yet, the past week has seen new terror arrests in Belgium and an unspecified warning of a gun or bomb attack sent to several European capitals.
In New York, the operation is expected to begin in the early hours of New Year's Eve. Police will start by closing off roads and setting up checkpoints where those attending the countdown will be screened.
No backpacks or duffle bags will be allowed into the area and police officers have been empowered to shut down the event and evacuate the public if needed.
"We are very confident that New Year's Eve in New York City will be the safest place in the world to be," said Mr James Waters, who heads the counter-terrorism unit of the New York Police Department.