3. Conversion of energy (Energy and work)

Energy can take many different forms. Muscle power has always been one variety of using energy. But what happens to the energy we use?
Where does the energy go if we pull up a load on a chain? Does it contain more energy at the top or at the bottom? What happens if we make life easier for us and use a pulley?
And where do people get the energy from to lift a load, with or without a pulley?