The Citigroup Center is a 59-story, 915-foot-tall (279 m) tower clad in glass and metal facade.

Structural engineer William LeMessurier designed the tower to be supported by four massive columns 114 feet (35 meters) high, positioned at the center of each side, rather than at the corners.
This design allowed the corners of the building to cantilever 72 feet (22 meters).
To help accomplish this, LeMessurier employed a system of stacked load-bearing braces, in the form of inverted chevrons.
Each chevron is designed to distribute tension loads (due to wind) to their center, then downward into the ground through the uniquely positioned columns.

The roof of Citigroup Center slopes at a 45-degree angle.
Designers originally intended it to be terraces for apartments, and later revised it to contain flat-plate solar collectors, to produce hot water which would be used to dehumidify air and reduce cooling energy.
However, they eventually dropped this idea because the positioning of the angled roof meant that the solar panels would not face the sun directly.
The Citigroup Center is a 59-story, 915-foot-tall (279 m) tower clad in glass and metal facade.
Structural engineer William LeMessurier designed the tower to be supported by four massive columns 114 feet (35 meters) high, positioned at the center of each side, rather than at the corners. This design allowed the corners of the building to cantilever 72 feet (22 meters). To help accomplish this, LeMessurier employed a system of stacked load-bearing braces, in the form of inverted chevrons. Each chevron is designed to distribute tension loads (due to wind) to their center, then downward into the ground through the uniquely positioned columns.
The roof of Citigroup Center slopes at a 45-degree angle. Designers originally intended it to be terraces for apartments, and later revised it to contain flat-plate solar collectors, to produce hot water which would be used to dehumidify air and reduce cooling energy. However, they eventually dropped this idea because the positioning of the angled roof meant that the solar panels would not face the sun directly.
Citigroup Center