The first transatlantic radio message (1901) : Cornwall to St John's

Following the successes of his British and Italian experiments at home, Marconi became obsessed with the idea of sending messages across the Atlantic. He built a transmitter, 100 times more powerful than any previous station, at Poldhu, on the southwest tip of Cornwall and in November 1901 installed a receiving station at St. John's, Newfoundland. On December 12, 1901, he received signals from across the ocean - three dots representing the letter 'S' heard out of the background static.
The achievement has long been controversial - in theory, medium wave radio signals cannot carry that far during the day. But it is possible that Marconi may unknowingly also have been transmitting on the short waves as well.
Whatever the truth of it, news of Marconi's reported feat spread rapidly around the world, and he was acclaimed by outstanding scientists, including Thomas A. Edison. From now on, telegraphy and telephony would no longer be reliant on cables to cross oceans, or span continents.