Which came first, the internet (ARPANET) or the World Wide Web?

the internet (ARPANET) came first, by 20 years. The first message was sent between two networked computers.

Side by side

the internet (ARPANET)

On 29 October 1969 a team at UCLA tried to send the word "login" to Stanford. The system crashed after two characters, so the first message ever sent over the internet's ancestor was "lo". By the end of that year the network had four nodes. The internet is twenty years older than the Web, and confusing the two is the single most common error in this whole subject.

the World Wide Web

Berners-Lee circulated his proposal in March 1989, built the first browser and server by the end of 1990, and CERN put the software into the public domain in 1993. The Web is twenty years younger than the internet: the internet is the network, the Web is one service running on it, and email and file transfer both predate the Web by decades. The first website went live in December 1990 and is still online.