ARPANET and the Birth of the Internet

On October 29, 1969, a graduate student at UCLA tried to log in to a computer 350 miles away at the Stanford Research Institute. The system crashed after he typed the first two letters, so the first message ever sent over the ARPANET read simply "lo." It was an unglamorous beginning for a network that would remake the modern world. The project was funded by the Advanced Research Projects Agency, a Pentagon office created after the Soviet launch of Sputnik to keep the United States ahead in technology.

ARPANET's breakthrough was a then-radical idea called packet switching, which broke messages into small pieces that could travel independently across the network and reassemble at the other end. This made the network resilient and efficient, with no single point of failure — a property often, and only partly accurately, attributed to fears of nuclear attack. The real motive was more practical: letting researchers share scarce and expensive computing resources across distant universities.

The leap from ARPANET to the internet came in the 1970s, when Vinton Cerf and Robert Kahn devised a common language, TCP/IP, that let separate networks talk to one another. Adopted across ARPANET on January 1, 1983, the protocol turned a single government network into a network of networks — the architecture that still underlies the internet. Email, which had appeared on ARPANET in 1971, quickly became its most popular use.

The system stayed largely academic and governmental until 1989, when British scientist Tim Berners-Lee invented the World Wide Web, giving ordinary users an easy way to navigate it. Commercial restrictions on the network lifted in the early 1990s, and the internet exploded into public life. What began as a Cold War experiment in resource-sharing became the central nervous system of the global economy and culture.