Carbon nanotubes are microscopic cylinders made from rolled-up sheets of graphite with a thickness of one atom. Depending on how the atoms are arranged, carbon nanotubes can be hundreds of times stronger than steel while weighing significantly less. They can conduct electricity at least as efficiently as copper.
According to MIT, nanotubes can be millions of times longer than they are wide. No other substance known to man can be manufactured with such a large length-to-diameter ratio. Carbon nanotubes are efficient conductors of heat and can withstand temperatures up to 2,000 degrees Celsius. Although they were discovered in 1991, as of 2014, carbon nanotubes are still too costly and complex for large-scale commercial production.