A pulley is another basic contraption that lifts huge things by combining a rope or cable with a wheel and axle. In modern elevators, pulleys with huge metal cables are employed. The cable is wrapped around the wheel and axle's groove. The cable is pulled by an electric motor, which lifts the automobile between levels. Pulleys were first invented in the 1800s and have been improved upon since then. They are still used today in many applications where space is at a premium but where large loads need to be moved or lifted. The word "elevator" comes from the French autoroute pour l'élévation de tonnerre (the road for the elevation of thunder), because these machines were used to raise heavy bells into place inside churches. In modern buildings, elevator machines use electricity or hydraulic power to run motors that turn wheels or gears that in turn pull cables or belts attached to axles beneath the car. These cables or belts can be made of steel or rubber, depending on the application. Elevator cars themselves are usually made of wood, aluminum, or stainless steel. Elevators are indispensable in tall buildings, where they make life easier for people who have to climb up lots of stairs every day. They are also useful for moving large objects from one level to the next in factories and warehouses. Finally, elevators provide a safe way to travel quickly and conveniently between different floors.