(click on the pics for bigger versions)
This is the outside of the building the houses the ATLAS control room as well as the access shafts to the ATLAS cavern.
This is right as you walk in to the main building. You can see the huge yellow cranes (which were used to lower ATLAS down piece by peice) overhead, as well as make out one of the two huge access shafts right on the other side of the green fence.
This is looking down the access shaft (which is about 80 meters deep) into the ATLAS cavern.
These green phone booth looking things are retina scanners that you have to go through to access the elevator that will actually take you down into the cavern.
Here you can see the two types of muon chambers used on ATLAS as well as the beam pipe entering the detector. Particles enter from the LHC on the right side of the photo traveling in the silver pipe right in the middle of the picture. The large blue cylinder is solid shielding. The muon chambers on the right side of the picture are used to detect the most energetic particles from the collisions, that's why they are so far from the interaction point. These two pieces of the muon spectrometer are also the only two pieces of the detector that you can actually see when it's all closed up. Everything else is hidden behind the large wheels.
Another view of the muon spectrometer.
Another view of the muon chambers. This is also the only piece of the detector not yet fully assembled (assembled doesn't mean working though). You can see the gaps where the engineers are still installing chambers right up until the last minute.
Totally.
These things are the fire prevention system. Allegedly if there is a fire in the cavern these things will fill the entire cavern with some super crazy foam (in like 20 min) that will put the fire out without harming any of the pieces of the detector. Not sure I believe that.
Here you can see some of the muon chambers getting lowered in to the cavern, through the access shaft, for installation.
This is just some of the electronics that make up the level1 triggers. ATLAS will produce 1 petabyte of raw data per second when the LHC is running at it's design luminosity and energy, so these level1 triggers would start cutting that down into a somewhat more manageable amount.
Finally, if you want some perspective of what you were looking at, here is a diagram of the whole detector.
