tbutler | Hoover's [Broad] Sweep

I think this is probably about as close as you can get to putting all of Hoover Dam into one shot, without an aerial view. (Even a shot from the bridge walkway hides some of the features behind the dam.)

From the left: Lower-left, the Arizona (south-east) spillway. Upper-left, the visitors' center parking garage. To the right of the parking garage, the new (current) visitor's center. Then the dam itself. Just above and to the right of the dam, the pale rectangle is the original visitor's center from the 1930s:

The four towers at the middle: Intake towers for the hydroelectric generators at the base of the dam. Water gets sucked in through the towers, run through pipes to the generator room, with any extra going to a set of outlets downstream from the generators:

When I first started visiting the dam, the water was nearly up to the intake tower walkways - see the pics someone else posted here for an example. It's scary to see how far the water levels have dropped.

In between the two rearmost towers (on the Nevada side), you can see the Spillway House, a glass-walled event space that hangs out over the water:

Doesn't seem to be open to the public normally, but I bet they've got a great view.

Below the Nevada intake towers, you can just see the first of the scenic overlooks on the Arizona side, with a stairway leading down to the main Arizona-side parking.

Finally, at far right is the Nevada (northern) spillway. The concrete lip is set far enough below the top of the dam that when the lake comes close to overflowing, water goes into the spillway instead, and diverted through the old construction tunnels to come out below the dam, as shown in the diagram above. Here's a closer look at the Arizona spillway, so you can get some idea how it works: