WELLFLEET, Mass. -- One hundred years ago today, a young Italian inventor named Guglielmo Marconi stood on a sandy bluff on Cape Cod and sent a 54-word greeting from President Theodore Roosevelt across the ocean to England's King Edward VII.
A few hours later, the king responded, completing a dialogue that at the time seemed like pure magic.
Marconi had launched the era of global wireless communications.
"It rivals the Wright brothers at Kitty Hawk," says Bob Doherty, president of the Marconi Radio Club. "Marconi's experiments evolved into radio as we know it today. The events of 100 years ago paved the way for today's other wireless tools, including cell phones and pagers."
To mark the centennial, members of the club have been staging a weeklong radio marathon, communicating with other amateur radio enthusiasts around the world from an old Coast Guard post not far from the site of Marconi's original radio station. Working around the clock, the radio hams expect to log more than 10,000 transmissions by week's end.
The event culminates Saturday night with the worldwide transmission of a message from President Bush. Marconi's daughter, Princess Elettra Marconi, will be on the Cape, while her son, also named Guglielmo Marconi, will be at the family's ancestral home in Bologna, Italy, to receive the message from his mother.
Marconi, who was 28 at the time of the breakthrough, "had everybody against him," says the princess, who is in her early 70s and gained her title by marrying an Italian nobleman. "He was so young and all the big scientists, like Edison, were saying it wasn't possible. He had the intuition. He knew he could succeed. And he succeeded."
Each summer thousands of tourists visit the beach that now bears Marconi's name. Yet few realize that this was the place where modern communications were born.
Today, the site is under water because of erosion. At very low tides, a few remnants of its concrete foundations are visible beneath the surface. The events of Jan. 18, 1903, are commemorated with a small monument high on the sandy bluff.
"Every time you dial your cell phone, every time you turn on the car radio and hear a reporter broadcasting live via satellite from Saudi Arabia -- all of that was made possible by what Marconi did," says Maria Burks, superintendent of the Cape Cod National Seashore. "That's how far we've come in 100 years."
Marconi's station was at the easternmost point of the cape. Its four 210-foot wooden towers rose from the dunes and beach grass. He built a similar station in Cornwall, at England's southernmost tip, and one on Cape Breton Island, Nova Scotia.
Using Morse code, Marconi tapped out Roosevelt's message, which was relayed through Nova Scotia and on to Cornwall via radio waves.
The invention was crude by contemporary standards; no actual voice was transmitted. But up to then, telecommunication consisted of telegraph transmissions that required a cable.
Marconi had conducted similar experiments over shorter distances. And in 1901, he made his first successful trans-Atlantic radio transmission, broadcasting the letter "S" in Morse code from St. John's, Newfoundland, to Cornwall.
But his early work was largely regarded as "crackpot technology," says Burks.
That changed with Marconi's broadcast from Wellfleet. He won the Nobel Prize for physics in 1909.
The Wellfleet radio station operated until 1918, receiving perhaps its most compelling message in 1912, when its operator received a transmission from the Titanic just hours before it sank.