International Marconi Day/IMD is a 24-hour amateur radio event held annually to celebrate the birth of Guglielmo Marconi on the 25th April 1874. Organized by the Cornish Amateur Radio Club, IMD takes place each year on the weekend closest to Marconi's birthday, April 25.

Guglielmo Giovanni Maria Marconi, 1st Marquis of Marconi FRSA was an Italian inventor and electrical engineer, known for his creation of a practical radio wave-based wireless telegraph system

Nobel Prize in Physics 1909 was awarded jointly to Guglielmo Marconi and Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy."