50 years ago, Marty Cooper stood on a corner of Sixth Avenue in New York and took a phone book from his pocket. He then punched a number into a large, cream-coloured device and put it to his ear while incredulous passers-by gave him strange looks.
Who did he call? Well, Mr Cooper, an engineer at Motorola, couldn't resist ringing his counterpart at rival firm Bell Laboratories, to triumphantly tell him he was calling from "a personal, handheld, portable cell phone". He recalls there being silence on the end of the line, that April day in 1973, reports the BBC. "I think he was gritting his teeth," says the 94-year-old, laughing.
Bell Laboratories had been focusing on developing a car-based phone instead, he says. "Could you believe that? So we had been trapped in our homes and offices by this copper wire for over 100 years - and now they were going to trap us in our cars!"
The commercial version of Marty Cooper's prototype, the Motorola Dynatac 8000X, took a long time to get to market after that momentous first call. It was released 11 years later, in 1984. It would cost the equivalent of $11,700 if bought today, says Ben Wood, who runs the Mobile Phone Museum.
"Basically, it was just dial the number and make the call," Mr Wood explains.
"There was no messaging, no camera. Thirty minutes of talk-time, 10 hours to charge the battery, about 12 hours of stand-by time and a 6in (15cm) antenna on the top." It was also rather heavy, weighing on at 1.7lbs - about the weight of a pineapple.
Ah, those were the days!
Century Old Prediction of Pocket Phones: Over one hundred years ago, English cartoonist and caricaturist W. K. Haselden did a strip on "pocket telephones". Remarkably prescient! See strip...