Dad and I took the Hard Hat tour.  It lasts a bit over an hour and takes you inside of the structure.  This is the generator room.  There are seven generators.  Number 6 is down for repairs so it's light is not on (far back near the end).  The ceiling has two moving cranes (with the yellow P&H signs).  The Nevada side is a duplicate of the Arizona side.

The level below the generator room - the turbine room.  The red hydraulic ram adjusts the angle of the water jets against the turbine wheel.  In the turbine pit are small green pivots - each of these represents a water jet.

 

The turbine output shaft.  It spins (I think) at 180 rpm.  The large bulge in the shaft is a coupler.  The total shaft length is about 65 feet.

 

Outside of the generator/turbine buildings.

The building in the top right is for controlled water releases (water over the spillways are classified as uncontrolled releases).  The left four openings are sealed and the right two are open.  All six used to be in operation until an upgrade was performed on the valves.  The original valves did not let much water out even at full opening.  Four of the valves were capped and the last two were fitted with gate valves.  The gate valves, when open, can pass three times the capacity than the original valves, thus only two are needed.  The same is on the Nevada side.

One of the tunnels inside of the dam.  I greatly lightened the picture so that the curve of the tunnel is visible.

 

Looking out one of the four air vents in the face of the dam.

 

What the tunnel looked like going to the air vent.