"World Skyscraper Day" was celebrated on September 3rd on the birthday of architect Louis H. Sullivan, who is called the Father of Skyscrapers and is widely believed to have designed the first ones.

The Home Insurance Building in Chicago is generally considered the world's first skyscraper. Completed in 1885, it was the first to use a curtain wall construction on a steel frame. Now there are nearly 23,000 skyscrapers across the globe, with 3 cities - Hong Kong, Shanghai and Shenzhen - having 5,650 alone!

To celebrate World Skyscraper Day, companies encouraged the public to climb their closest skyscraper and take photos of their local skyline, or learn more about the engineering behind them.