A diagrid is a framework of diagonally intersecting metal, concrete, or wooden beams that is used in the construction of buildings and roofs. It requires less structural steel than a conventional steel frame. Hearst Tower in New York City, designed by Norman Foster, uses 21 percent less steel than a standard design. The diagrid obviates the need for columns and can be used to make large column-free expanses of roofing. Another iconic building designed by Foster, 30 St Mary Axe, in London, UK, known as "The Gherkin", also uses the diagrid system.

The Hearst Tower is a building at the southwest corner of 57th Street and Eighth Avenue, near Columbus Circle, in the Midtown Manhattan neighborhood of New York City, United States. It is the world headquarters of media conglomerate Hearst Communications, housing many of its publications and communications companies. The Hearst Tower consists of two sections, with a total height of 597 feet (182 m) and 46 stories. The six lowest stories form the Hearst Magazine Building, designed by Joseph Urban and George B. Post & Sons, which was completed in 1928. Above it is the Hearst Tower addition, which was completed in 2006 and designed by Norman Foster.