How the Internet Was Born

Late on the night of 29 October 1969, a graduate student at UCLA sat at a computer terminal and typed 'l', then 'o'. The system at the other end — at Stanford Research Institute, 560 kilometres away — received the letters. Then it crashed.

The message was supposed to be 'login'. What arrived was 'lo'. It was, accidentally, the perfect first greeting from one machine to another: lo.

The experiment worked. ARPANET — the first internet — had sent its first message. Three weeks later, a full login worked. The network was real.

Why the Military Funded It

The Advanced Research Projects Agency (ARPA) was a US Defence Department organisation created in 1958, two months after the Soviet Union launched Sputnik and sent American military planners into a panic. ARPA's job was to fund scientific research that might have military relevance — and in 1966, that included the idea of networking computers.

The military motivation was partly practical: expensive computers at different universities couldn't share resources easily. But there was also a Cold War subtext. The existing telephone network was vulnerable: a nuclear strike on a switching centre could cut communication across entire regions. An ARPA engineer named Paul Baran had proposed a different kind of network — one with no central hub, where messages could route around damaged sections automatically.

That idea — redundancy by design — became the internet's founding principle. Build the network so that the destruction of any single point doesn't stop communication. Information finds another path.

Packet Switching: The Key Invention

The telephone network of 1969 worked by circuit switching: when you made a call, a dedicated line was reserved from your phone to the other person's phone for the entire duration. Nobody else could use that capacity while your conversation was happening.

This was wasteful and fragile. Wasted because most of a voice conversation is silence; the reserved line sits idle. Fragile because if any link in the dedicated circuit broke, the call dropped completely.

Packet switching works differently. A message is broken into small chunks — packets — each labelled with its destination address. The packets are released into the network independently. Each router they reach reads the destination and decides the best next hop. Packets from the same message might travel completely different routes, arriving out of order. The receiving computer waits until all packets arrive, then reassembles them.

This is radically more robust. If a router fails, packets find a different path. There's no dedicated circuit to break. The network heals around damage automatically — exactly what ARPA wanted.

Try the simulator above. Knock out routers one by one. The packet reroutes until you've eliminated every path — then, and only then, does delivery fail.

Growing Up: From ARPANET to Internet

ARPANET connected four universities in 1969. By 1971, 15. By 1981, over 200 computers worldwide. In 1983, a crucial decision was made: the entire network would switch to a new common language called TCP/IP.

Before TCP/IP, different networks spoke different protocols and couldn't easily talk to each other. TCP/IP was a universal standard: any computer that implemented it could communicate with any other. The day everyone switched — 1 January 1983 — is sometimes called "Flag Day." It's when the internet in its modern sense truly began.

Through the 1980s, the network expanded beyond military and academic use. In 1991 it opened to commercial traffic. By 1993, the World Wide Web had made it accessible to ordinary people. The rest happened very quickly.

The Internet Is Not the Web

This is one of the most common confusions in technology, and it matters.

The internet is the global network of connected computers — the physical infrastructure of cables, routers, and the TCP/IP protocol. It is the pipes.

The World Wide Web is one application that runs on those pipes — a system for linking documents via clickable hyperlinks, accessed through a browser. Email, video calls, online gaming, peer-to-peer file sharing — all separate applications, all using the same internet pipes, none of them the Web.

Tim Berners-Lee invented the Web in 1989. The internet had existed for 20 years before that. When someone says "I use the internet," they usually mean the Web. But the distinction is real and useful: the internet is infrastructure, the Web is one thing built on it. And if the Web were replaced by something else tomorrow, the internet would still be there underneath.

The Undersea Cables Nobody Talks About

The internet feels wireless and ethereal. It isn't. About 95% of all international internet traffic travels through undersea fibre optic cables — actual physical cables laid on the ocean floor, thinner than a garden hose, spanning thousands of kilometres.

There are around 500 of these cables. They're occasionally damaged by ship anchors, undersea landslides, or — rarely — deliberate cutting. When the 2006 earthquake near Taiwan damaged several cables, internet speeds across Asia dropped dramatically for weeks. The redundancy works better in some regions than others. A handful of critical cable landing points handle an enormous fraction of global traffic.

The internet is more physical, and more geographically concentrated, than most people imagine.