The crucial developments for modern skyscrapers were steel, glass, reinforced concrete, water pumps, and elevators. Until the 19th century, buildings of over six stories were rare. So many flights of stairs were impractical for inhabitants, and water pressure was usually insufficient to supply running water above about 15 metres (50 feet). However, despite this lack of sanitation, high rise housing dates back to the 1600s in some places. The Romans built apartment buildings sometimes 7 to 8 stories high. These buildings were unstable and dirty and often caught fire due to careless inhabitants. In Edinburgh, Scotland for instance, the defensive city wall defined the boundaries of the city. With limited land area for development the houses increased in height. Buildings of 11 stories were common, and there are records of buildings as high as 14 stories. Many of the stone-built structures can still be seen today in the old town of Edinburgh particularly in the 'Wynds' and 'Closes' just off the Royal Mile.
The oldest iron framed building in the world is The Flaxmill (also locally known as the "Maltings") in Shrewsbury, England. Built in 1797, it is seen as the "grandfather of skyscrapers” due to its fireproof combination of cast iron columns and cast iron beams developed into the modern steel frame which made modern skyscrapers possible. It unfortunately lies derelict and needs much investment to keep it standing. On 31 March 2005, it was announced that English Heritage would buy the Flaxmill, so that it could be redeveloped.
The first skyscraper was the ten-story Home Insurance Building in Chicago, built in 1884–1885. While its height is not considered unusual or very impressive today, the architect, Major William Le Baron Jenney, created the first load-carrying structural frame. In this building, a steel frame supported the entire weight of the walls instead of the walls themselves carrying the weight of the building which was the usual method. This development led to the "Chicago skeleton" form of construction. After Jenney's accomplishment the sky was truly the limit so far as building was concerned.
Sullivan's Wainwright Building building in St. Louis, 1890, was the first steel frame building with soaring vertical bands to emphasize the height of the building, and is, therefore, considered by some to be the first true skyscraper.