The concept of an elevator is incredibly simple -- it's just a compartment attached to a lifting system. Tie a piece of rope to a box, and you've got a basic elevator. Of course, modern passenger and freight elevators are a lot more elaborate than this. They need advanced mechanical systems to handle the substantial weight of the elevator car and its cargo. Additionally, they need control mechanisms so passengers can operate the elevator, and they need safety devices to keep everything running smoothly.