Arpanet

The internet's predecessor, the ARPANET, transmitted its first message in 1969.

ARPANET went online in September, 1969, and connected four computers located in California and Utah.

The ARPANET was especially important to the Internet project, and was often called the backbone network because it was the central WAN that tied researchers together.

It allowed the ARPANET, a single network, to develop into the Internet—an internetwork of hundreds of thousands of networks.