Metal is probably my favourite material. It is so malleable and yet so hard and durable, it can last thousands of years and yet you can always melt it down and shape it again, over and over again, indefinitely. It is the ultimate sustainable material. 
There are so many techniques that produce different results: you can cast complex three dimensional shapes, electro-form pieces to produce light and unique results and laser cut and mill it to achieve very precise and fine lines; then you can weld or solder all the pieces together. First the metal needs to be annealed to make it softer, then you can shape it in any way you want, bending, crushing or folding it. My favourite part is welding or soldering- it is a magical process as the heat of the fire transforms solder or lead into liquid metal that glues all the pieces together. Finishing is where its beauty is revealed; the solder marks and fire stains are removed and the true colour of the metal comes out, be it brass, copper, steel, silver or even gold.