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Citigroup Center
New York, New York

This landmark skyscraper was the world’s 9th tallest upon completion, employing several structural innovations: four mid-side trussed columns at the base support the tower, which cantilevers over the city block below; loads are directed to the main columns by 15-story super braces; the world’s first tuned mass damper controls building motion under wind loads. This tower’s legacy continues to be the ingenuity of design and its peerless execution.