Elevators

We begin our history of elevators by looking at ancient civilizations, learning that some early civilizations used animals or slaves to lift heavy objects and that the Egyptians had hoists to build the pyramids. We find out that originally, people didn't usually ride on elevators because the kept breaking and werevery dangerous, so until safety brakes were invented, buildings generally didn't get higher than five stories tall. Then, Elisha Otis invented the safety brake, a device that kicked in and stopped the elevator if the rope snapped. These days, elevators have allowed us to build huge skyscrapers and they've also made it easier for miners to work underground. When skyscrapers are built, one of the first things that they have to keep in mind is the elevator. They begin by creating the core, into which they have to carefully place openings where the doors for the elevators will be. Once the core is built, they can build the actual structure around it. We learn that before elevators