Says it all right there. You want to see inside the world’s largest particle accelerator? Street View will take you into the underground tunnels:
We’re delighted that CERN opened its doors to Google Maps Street View allowing anyone, anywhere in the world to take a peek into its laboratories, control centers and its myriad underground tunnels housing cutting-edge experiments. Street View also lets scientists working on the experiments, who may be on the other side of the world, explore the equipment they’re using.
Needless to say, this is hardcore porn for electronics fetishists. Giant circuits! Heavy ion detectors! Huge arrays of… THINGS!