One of the largest security operations in the U.S. is underway: protecting thousands of world leaders and their teams during the annual United Nations General Assembly (UNGA) in New York.

As diplomats convene for speeches and networking this week, CNN and select media were granted access to two high-security control rooms at the UN headquarters, navigating through a series of unmarked corridors.

Notably, both rooms feature extensive walls of monitors displaying feeds from around the UN complex. With a total of 1,400 cameras installed—some cleverly concealed—security personnel monitor various areas, including doors, garages, hallways, and driveways. UN security officials acknowledge that while it’s impossible to monitor all cameras simultaneously, there are always personnel actively reviewing the feeds.

If an individual encounters issues with their credentials while trying to enter the complex, an alarm will sound, with an automated message declaring “Rejected! Rejected! Rejected!”

Security for this event is a collaborative effort involving the UN, the New York Police Department, the Secret Service, and diplomatic security teams. This year, over 22,000 delegates attended the UNGA.

Due to the recurring nature of this event, security teams maintain detailed files to improve their response each year. “Knock on wood; we have never had a security incident related to heads of state here. We have pulled out all the stops,” stated U.S. Ambassador to the UN Linda Thomas-Greenfield.

The NYPD and diplomatic security also coordinate motorcades for world leaders traveling to and from their hotels, contributing to significant traffic delays. Many leaders this year have engaged in events across the city, from ringing the bell at the New York Stock Exchange to connecting with U.S. constituents.

Despite increasing criticism of the United Nations and tense exchanges between ambassadors, handling security threats has always been part of the job.

Past incidents include a woman in crisis driving up to the UN entrance last New Year’s Day and a 2002 shooting incident when a postal worker breached the perimeter, resulting in heightened security measures.

UN security officials remain focused on maintaining a safe environment, and so far, their efforts appear to be effective.