ARPANET, experimental computer network that was the forerunner of the Internet. The Advanced Research Projects Agency (ARPA), an arm of the U.S. Defense Department, funded its development in the late 1960s. Its initial purpose was to link computers at Pentagon-funded research institutions over telephone lines.| Encyclopedia Britannica
The ARPANET made its splashy public debut in 1972. Why exactly was it such a big deal?| twobithistory.org