Wikipedia's image repository includes a photo of the NeXTCube that Tim Berners-Lee ran the first-ever Web server on, at the CERN lab in Geneva, Switzerland:
This NeXT workstation (a NeXTcube) was used by Tim Berners-Lee as the first Web server on the World Wide Web. 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!!"
(Thanks, Fipi Lele!)