The first Web Server on the WWW was this NeXT workstation (a NeXTcube), used by Tim Berners-Lee. Today, it is kept in Microcosm, the public museum at the Meyrin site of CERN, in the Canton of Geneva, Switzerland.
The document resting on the keyboard is a copy of "Information Management: A Proposal," which was Berners-Lee's original proposal for the World Wide Web.
The label on the cube itself has the following text: "This machine is a server. DO NOT POWER IT DOWN!!"
Just below the keyboard (not shown) is a label which reads: "At the end of the 80s, Tim Berners-Lee invented the World Wide Web using this Next computer as the first Web server."