When CERN's LHC is running, the detectors are awash in deadly gamma rays. During maintenance phase is the only time it is relatively safe to visit them, and also various parts of the detectors may be separated from one another so it is possible to get a better look at them. Read the article to find out how they move around pieces of the building-sized Compact Muon Solenoid, while you're wondering how big a Full-Sized Muon Solenoid would be:

[Note that there are three slide shows - two are on the second page.]

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A rare LHC tour—avoiding radiation to see scientific history up close
With hardware still disassembled for service, Ars snuck underground to see LHC up close.
by John Timmer - Apr 3, 2015

CESSY, France—As we drive through small villages in Eastern France, some for the second time, it's becoming increasingly clear that my tour guide is lost. She's got a stack of printed Google Maps, but, without a clear indication of where we actually are, it's tough to tell where in the stack she should be looking.

Eventually, on the other side of a corn field, she spots a building that looks out of place. Someone apparently ripped this structure out of an office park in New Jersey and dropped it into France. Before long, we step onto an elevator and step out into a scene that wouldn't look out of place in a science fiction movie. A building-sized heap of electronics dominates the underground cavern before us, and this contraption has an equally sci-fi-ish name: the Compact Muon Solenoid.

Best known for helping physicist Peter Higgs earn his Nobel Prize for the discovery of the Higgs boson, the CMS is one of two general purpose particle detectors built on the Large Hadron Collider (LHC) at CERN, which extends from Switzerland and into France. Normally when the LHC runs, the chambers housing the detectors experience intense radiation; security systems keep pretty much anyone from entering (and for good reason).

But for the past two years, the building hasn't been used for physics. Instead, physical repairs and improvements to all of the detectors, as well as the LHC itself, were made. A bit over a year ago, while the LHC was shut down and partly disassembled, I was lucky enough to be invited underground to see its massive detectors and walk the vast tunnels housing the particle accelerator itself....

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http://arstechnica.com/science/2015/04/a-rare-lhc-tour-avoiding-radiation-to-see-scientific-history-up-close/1/