What was Marconi Guglielmo famous for?

Italian born Guglielmo Marconi was most famous for inventing and transmitting the first wireless signals across the Atlantic Ocean. According to the Nobel Prize Organization, in 1900, Marconi received his famous patent number 7777 for tuned or syntonic telegraphy.

In December 1901, Marconi proved that wireless waves were not affected by the curvature of Earth. He used his patented invention for transmitting the first wireless signals across the Atlantic between Poldhu, Cornwall and St. John's, Newfoundland; the distance covers 2100 miles.

As a direct result of his work, Marconi received the 1909 Nobel Prize in physics, along with fellow scientist Karl Ferdinand Braun.