Internet celebrates its 40th birthday

Many happy returns to the internet, which celebrates its birthday today (29 October 2009). It's exactly 40 years since Professor Leonard Kleinrock sent a message between two computers, 200 miles apart.

At 2100, on 29 October 1969, engineers at the University of California in Los Angeles (UCLA) and Stanford Research Institute (SRI) sent data to each other between what was then known as Arpanet.

It was named after the US Department of Defense's Advanced Research Projects Agency (Arpa) that commissioned the experiment.

Arpanet then became the internet in the 1970s; however, it didn't become popular and widespread until the 1990s when broadband became more affordable and widely available.

How much do you know about the internet? Take our 40 years of the internet quiz and see.