During a marathon 1200 mile trip that included speaking at Jefferson High in San Francisco and visitng the PAReX robotics club in Phoenix, I stopped off at Hoover Dam and took the "hard hat" tour - two hours of awe and disbelief. Some of these pictures are terrible not only due to low light but also because of the enormity of the object in view.

Never open a door that has a pressure valve on it.		The entire dam is filled with inspection and access tunnels and there is a nearly steady dripping of water seeping through the cement. This is good though; the cement is still curing and getting harder every year.
These stairs went down. Way down!		Protected access lights in the tunnels required some forethought so the forms could be built to accomodate them.
Giant tunnels were blasted into the granite walls downstream of the gap the dam was wedged into so the water pipes could be lain. The primary purpose of Hoover Dam was not to generate power but to regulate the flow of the Colorado river and protect against floods.
We're in the access space over one of the giant pipes that carries water from the intake towers to the downstream side - only a fraction of the water is used for power generation. The force of the water makes everything shake and is very loud. The pipe passing beneath this bridge is about 30 feet in diameter.		Two galleries down each side of the dam contain an array of hydroelectric generators. You can get a feel for the size based on the scale of the staircase. Also notice the overhead crane system for maintenance. 133 megawatts apiece. Zow!
Now we're down in the access tunnel beneath the level in the above picture. The line of vertical shafts couple the water turbine to the generator rotor.		Fortunately they had one of the generators apart for service. This is the coupling shaft. It weighs two tons - can you imagine the size of the lathe that turned it?
Here is the rotor removed from the generator. The centrifugal ducts at the bottom are not for water but for air flow to cool the coils.		A close shot of the commutator bars that the brushes press upon.
How would you know if you're overstressing the overhead crane? Use a scale inline with the lift straps. This scale relies on the calibrated deflection of the steel I-beam, like a torque wrench. It weighed over 9 tons itself and could carry a load up to 25.		Down on the generator gallery looking 750 feet up at the face of the dam. The top of the dam is a highway connecting Nevada to Arizona!
The dam is built in this timeless nouveau art style.		Aluminum had been freshly introduced into American architecture in 1932 and was used as trim inside and outside the buildings.
Outside of the generator galleries separated by the river.
A monument to the workers that died during construction of the project is flanked by two statues. I admired their sculpture as much as the technical design of the dam itself.
For more information please visit the official Hoover Dam website.