The invention of a safety device for the elevator made possible the construction of highrise buildings, thus enabling the traditionally horizontal city to turn to the vertical. In the mid-nineteenth century hotels and commercial stores were among the first building types to deploy elevators; with improvements in elevator technology, office buildings and apartment buildings adopted them. As structural advances made possible taller buildings new elevator technologies made possible easy and safe access to those floors. Hoisting and lifting devices were long a common feature in mines, on building sites, and for the loading of ships. Rarely more complicated than a pulley with a winch turned by hand or animal, or later powered by steam, the particular danger of these early forms of hoist was the absence of a safety device. Stretched or frayed ropes or cables might break causing the platform to hurtle to the ground. The key invention that made the hoist or lift safe for humans was a safety de...