Stone to Silicon

Communication · 1969

ARPANET

UCLA sends 'LO' to Stanford before crashing: the first message of the internet's ancestor.

On 29 October 1969 the first ARPANET link connected UCLA and SRI, using packet-switching Interface Message Processors built by BBN. Funded by the US Defense Department's ARPA, it grew to dozens of sites and became the testbed for email, TCP/IP and internet culture.

See it in the living treeWikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 3

What it led to 2

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Related measurements

The dashed line marks when it first worked.

Internet users in the United States Latest: 322M people (2024) Source: Our World in Data

Share of people online Latest: 73.6 % (2025) Source: Our World in Data