How high can you build a skyscraper?

How high can you build a skyscraper? The projected 1km-high building in Jeddah, Saudi Arabia is set to be the world’s tallest, but what’s interesting is that it was meant to be a kilometre-and-a-half. The first major problem is wind: what feels like a gentle breeze at ground level can feel like a howling gale 500m up – as engineer William LeMessurier found out in 1978 when he just completed the 278m Citicorp Center in New York. An undergraduate architecture student asked him whether the building could blow over in the wind, and LeMessurier discovered to his horror that the design had accounted for perpendicular winds, but not winds angled at 45 degrees to the building. Workmen were sent in at night to make the building safe by welding steel plates to the wind braces., and this was kept a secret from the public for nearly 20 years.