We are certainly making progress in subtler ways; energy efficiency has dramatically improved, and mass customization techniques are allowing for new types of structures with fine nonrepeating detail and an organic feel. There are also certainly drawbacks to structures like dams, which can damage ecosystems despite providing clean power, and I don't advocate aggressive damming of every valley in sight. Also, there are also certainly other areas in which America is excelling, including most major internet businesses. However, it seems that new construction and civil engineering projects don't fire our imaginations anymore. I don't want to see our urban development mired in a morass of entrenched interests and excess regulation, leading us to gradually fall behind as it becomes too difficult to make progress. For example, building a modern SF-LA high speed rail seems hopelessly complex and political.
Anyway, the visual experience of Hoover Dam, built in a jagged and lifeless canyon of burnt-brown with a tangle of power lines emerging from a central core deep in the ground, is not unlike a mid-1900s rendition of Mordor. The stark landscape helps add to the feel of the project's audacity.
From the interior... 80-year-old grafitti, among other things:


Faraway rocks had a burnt look -- here's a quick feel for what they'd look like without all that silly air in the way:
Full Flickr set here