The cantilever exists because the northwest corner of the building site is occupied by St. Peter's Lutheran Church.
When Citicorp Center was built in the 1970s, the church allowed Citicorp to demolish the old church building and build the skyscraper under one condition: a new church would have to be built on the same corner, not attached to the Citicorp building and no columns passing through it, because the church wanted to remain on the site of the new development, near one of the intersections.
The church, at 619 Lexington Avenue with its entrance from 54th Street, has a theatre in its basement which is mainly used by the York Theatre.

To help stabilize the building, a tuned mass damper was placed in the mechanical space at its top.
This substantial piece of stabilizing equipment weighs 400 tons (350 metric tons).
The damper is designed to counteract swaying motions due to the effect of wind on the building and reduces the building's movement due to wind by as much as 50%.
Citigroup Center was the first skyscraper in the United States to feature a tuned mass damper.
In addition, in 2002, one of the columns was reinforced with blast-resistant shields of steel and copper as well as steel bracing to protect the building due to the possibility of a terrorist attack.

The building features double-deck elevators, which are separated to serve only odd or even floors.
People can travel between odd and even floors using escalators.

Various plazas were included as part of the building's construction.
 One such plaza exists below the cantilever, where there is an entrance to the New York City Subway station at Lexington Avenue/51st Street, served by the 6, <6>​​, E, and ​M trains.

From 1987 to 2009, the bank presented an annual toy train exhibition in the lower lobby.
The cantilever exists because the northwest corner of the building site is occupied by St. Peter's Lutheran Church. When Citicorp Center was built in the 1970s, the church allowed Citicorp to demolish the old church building and build the skyscraper under one condition: a new church would have to be built on the same corner, not attached to the Citicorp building and no columns passing through it, because the church wanted to remain on the site of the new development, near one of the intersections. The church, at 619 Lexington Avenue with its entrance from 54th Street, has a theatre in its basement which is mainly used by the York Theatre.
To help stabilize the building, a tuned mass damper was placed in the mechanical space at its top. This substantial piece of stabilizing equipment weighs 400 tons (350 metric tons). The damper is designed to counteract swaying motions due to the effect of wind on the building and reduces the building's movement due to wind by as much as 50%. Citigroup Center was the first skyscraper in the United States to feature a tuned mass damper. In addition, in 2002, one of the columns was reinforced with blast-resistant shields of steel and copper as well as steel bracing to protect the building due to the possibility of a terrorist attack.
The building features double-deck elevators, which are separated to serve only odd or even floors. People can travel between odd and even floors using escalators.
Various plazas were included as part of the building's construction.  One such plaza exists below the cantilever, where there is an entrance to the New York City Subway station at Lexington Avenue/51st Street, served by the 6, <6>​​, E, and ​M trains.
From 1987 to 2009, the bank presented an annual toy train exhibition in the lower lobby.
Citigroup Center