The world's first website was published on 6th August 1991

"Even if you can't name the inventor of the World Wide Web (It's Tim Berners-Lee!), you'll probably want to celebrate one of the information network's most important milestones. On August 6, 1991 -- 21 years ago -- Berners-Lee published the world's first website from a lab in the Swiss Alps.
So Happy 21st Birthday, WWW! Have a drink on us. As our friends over at HuffPost UK point out, the world's first website can still be visited today, more than two decades after its creation.
The site, originally found at the clunky URL "http://info.cern.ch/hypertext/WWW/TheProject.html," was updated frequently after launching; therefore, images of its earliest versions were never saved. Nevertheless, a later copy from 1992 is still preserved and welcoming visitors.
The bare-bones website was created, appropriately, to explain the World Wide Web to newcomers. "The WorldWideWeb (W3) is a wide-area hypermedia information retrieval initiative aiming to give universal access to a large universe of documents," the site reads, going on to explain how others can create their own webpages."
Source:  Huffington Post, 6th August 2012