A guitar carved from a block of silicon and based on a Fender Stratocaster, measured ten micrometres long - 1/20 the thickness of human hair. Made in 1997 in just twenty minutes by scientists at the Cornell University, New York, USA, each of its six strings were 0.05 micrometres thick, equivalent to 100 atoms laid end to end.When plucked, the strings vibrated, but at frequencies 1,000 times higher than the human ear can pick up. Each approximately 50 nanometres wide (around 100 atoms of Silicon), the strings could actually be plucked by an atomic force microscope and resonate. Examples like this guitar, which is the size of a human blood cell, are instrumental in demonstrating capabilities for micro-engineering structures that will be useful for medical and bio-engineering applications.