For centuries, some of the tallest buildings in the world were religious buildings, but few were ever more than 150 meters tall. Almost all of these buildings took decades or even hundreds of years to complete. However the invention of steel frames in the late 1800s meant that the walls did not carry the weight of a structure This development meant that suddenly much taller buildings were possible, and they could be built quickly. Skyscrapers had been born, and they were about to change the the face of our cities.