Guglielmo Marconi achieves on 12 December 1901 the first transmission of radio signals across the Atlantic, from Poldhu (Cornwall, UK) to Signal Hill (St. John's, Newfoundland, Canada), a distance of 3,400 km. It is a real operational and commercial milestone: it demonstrates that radio waves followed the curvature of the Earth beyond the horizon, against theoretical predictions. He receives the Nobel Prize in Physics in 1909. However, the fundamental principles of the system Marconi used — tuned transmission with four circuits — had been patented by Nikola Tesla in 1897 (patent no. 645,576). The US Patent Office initially rejected Marconi's application in 1900 due to Tesla's priority, and the US Supreme Court confirmed in 1943 (320 U.S. 1) that Marconi's patents had been anticipated by Tesla, Lodge, and Stone. Marconi's real contribution was operational and commercial — the practical demonstration at intercontinental scale and the building of the wireless telecommunications industry — not the invention of the underlying physical principles. In the domain of radiotelephony (voice transmission), Julio Cervera Baviera (Spain, 1902) precedes him according to Faus's research.