On August 6, 1991, at CERN (the European Organization for Nuclear Research), the world's first Web site went online.   It explained what the World Wide Web was, and gave general instructions on how to use it and be part of it.

Tim Berners-Lee, assisted by Robert Cailliau, had created this new system, developed the first "browser", and the first server (httpd or HyperText Transfer Protocol daemon).

They WorldWideWeb provided a hypertext protocol, interface, and domain name system for the worldwide series of interconnected computer networks known as the Internet. 

The Internet itself was an outgrowth of ARPANET was an outgrowth of the Advanced Research Projects Agency (the Advanced resarch Projects Agency Network),  a packet switching network developed by the Advanced Research Projects Agency (ARPA) created in 1958 by the United States government to maintain a technological edge in the wake of the Soviet Union's launch of Sputnik.

Conceived for the United States Air Force in a study by Paul Barand of the RAND Corporation, the Internet had been developed as a decentralized communication network that could survive a nuclear attack, and and enable maintenance of command and control over Air Force assets that would permit a counter-attack.

It is too early to write a history of the WorldWideWeb.  But from a single website in 1991, and aproximately 18,000 websites in 1995, the WorldWideWeb has grown to over 100,000,000 Web sites with domain names and content.