The Monadnock Building is a 16-story skyscraper located at 53 West Jackson Boulevard in the south Loop area of Chicago. The north half of the building was designed by the firm of Burnham & Root and built starting in 1891. At 215 feet, it is the tallest load-bearing brick building ever constructed. It employed the first portal system of wind bracing in the United States. Its decorative staircases represent the first structural use of aluminum in building construction. The later south half, constructed in 1893, was designed by Holabird & Roche and is similar in color and profile to the original, but the design is more traditionally ornate. When completed, it was the largest office building in the world. The success of the building was the catalyst for an important new business center at the southern end of the Loop.

A skyscraper is a tall continuously habitable building having multiple floors. Modern sources define skyscrapers as being at least 100 meters (330 ft) or 150 meters (490 ft) in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Historically, the term first referred to buildings with between 10 and 20 stories when these types of buildings began to be constructed in the 1880s. Skyscrapers may host offices, hotels, residential spaces, and retail spaces.