elisha otis -- elijah otis successfully demonstrated the safety device he had created. even of the elevator and he cut the device, and he did not fall. everyone was impressed by that. in 1857, the oldest brother's company installed their first passenger elevator on broadway in new york. believe it or not, many of those first elevators were actually started and stopped by a hand broke. >> what drove those old elevators? what was their motive power? >> in some cases, they might have even been hp. >> and then changed to electric? >> electric cited to come in the 1890's, and that was around the time when the elevator stopped from material handling and started to be used more frequently for passengers. in 1878, there was a demonstration of the other thing that allowed architects to build taller buildings was the advent of a higher quality steel manufacturing. in 19003, the first production year track models were introduced, that it was when things took off. >> that mostly happened in new york city? >> lower manhattan was the first place that took off, then chicago. those ear