The signal that earned Guglielmo Marconi his place in history was not a long one: just the Morse code dots of the letter "S". But those three short radio pips represented a giant leap for mankind. The signal, which had travelled some 2,000 miles over open water from a transmitter in Poldhu, Cornwall, to a shack on a windy Newfoundland hill, was proof that radio waves could "bend" around the curvature of the Earth and effectively jump the 100-mile-high wall of water that blocks the view of America from Britain. For Marconi, then a young Italian man (with Irish ancestry from his mother's side), and his faithful assistant, an ex-petty officer called George Kemp, straining their ears over a primitive wireless set, those faint radio signals proved triumphantly that Marconi had been right all along when he insisted that there was no insuperable barrier to sending radio waves from one corner of the planet to another.