Multi-wall carbon nanotubes, coloured scanning electron microscope (SEM) image. The image shows bundles of multi-walled carbon nanotubes (MWNTs) produced using ethylene gas and an iron catalyst at high temperature. A carbon nanotube is a one atom thick sheet of graphite, called graphene, rolled into a cylinder with diameter of the order of a nanometre. In MWNTs nanotubes are arranged concentrically. Carbon nanotubes have interesting properties that make them useful in a wide variety of applications including electronics, materials science, optics and even medicine. They exhibit extraordinary strength, and unique electrical and heat conductive properties. Photographed at the Arkema Laboratory Pilot in Lacq, France, where MWNTs are produced in bulk under