Forty years ago today (April 3, 1973), Martin Cooper made a phone call from a prototype Dyna-Tac handheld cellular phone.  The phone, which weighed about 2.5 lb, connected Cooper to Dr. Joel S. Engel, head of research at Bell Labs.

Update: From “8 Guys, 6 Weeks: How the Cell Phone Was (Finally) Invented,” The Atlantic

On April 3, 1973 — 40 years ago today — Cooper took an early model of Motorola’s DynaTAC phone (a brick phone weighing 2.5 pounds, measuring 9 inches long and 5 inches deep, and featuring about 20 minutes of battery life) to the streets of New York City. He pressed the phone’s “off hook” button. And he made a call to the land line of Bell Labs, where he was connected to his counterpart, and chief rival, Joel Engel. “Joel, this is Marty,” Cooper said, gleefully. “I’m calling you from a cell phone, a real handheld portable cell phone.”

Cooper, in doing all this, made quite a scene. Telephones, at that point, were not things you could just carry around with you as you walked. (Cooper liked to joke that the DynaTAC’s limited talk time wasn’t technically a problem — since “you couldn’t hold that phone up for that long.”) So a guy strolling around near Radio City Music Hall, talking animatedly into a large hunk of plastic, was a spectacle. Even for a city that was used to spectacles. “As I walked down the street while talking on the phone,” Cooper would later recall, “sophisticated New Yorkers gaped at the sight of someone actually moving around while making a phone call.”

And that, of course, was the point. “We wanted to do a dazzling demonstration,” Cooper said. The team’s goal wasn’t just to invent something; it was to let the world know, in as striking a way as possible, that the something had been invented. The demo would end, appropriately, with the technologist processing to the Midtown Hilton, where a gaggle of reporters were assembled for a press conference. Cooper would hand his phone to one of those reporters so she could call her mother in Australia.

Cooper, in other words, enjoyed — and exploited — the moment. “I made numerous calls,” he remembered, “including one where I crossed the street while talking to a New York radio reporter — probably one of the more dangerous things I have ever done in my life.”