In 1853 the American mechanic Elisha Otis demonstrated a safety brake at the New York Crystal Palace exhibition, cutting the hoisting rope of a loaded platform while standing on it to show that spring-loaded pawls would catch the guide rails and arrest the fall. His firm installed the first passenger safety elevator in a Broadway store in 1857. The device did not invent vertical hoisting, which was ancient, but it removed the fear of a snapped cable that had confined hoists to freight.
By making upper floors as safe and reachable as lower ones, the safety elevator inverted the value of building height and turned the top storey from the cheapest into the most prestigious space. Combined with steel framing it was a precondition for the skyscraper and the dense vertical downtown.