A few summers ago, my family traveled to Switzerland, ostensibly for hiking, but it was on the heels of the Higgs discovery, and we signed up for a tour at CERN. Among the items in their museum is the computer that ran the first web site. It was a NeXT cube, with a card taped to the side, humbly requesting that it not be turned off.
I'm still amused by the thought of a time when the entire world-wide-web could be brought down by accidentally turning off one computer!