While the interiors leave some design issues unsolved, the exteriors are well thought out. They are built of simple, durable and no-maintenance materials – steel, plywood and car-decking. No effort is made to soften this reality. The steel exterior is just allowed to rust naturally."
http://www.homedesignfind.com/green/not-your-fathers-mobile-home/
Frank Lloyd Wright's famous house is structurally unsound and presently propped up to keep it from falling into the creek. According to this article, it's not age, but bad engineering (and arrogance) on Wright's part that caused the problem: 
http://www.ce.memphis.edu/1101/interesting_stuff/fallingwaters.html
When I first went to Washington D.C. (about 15 years ago), I was stunned by the capitol dome. I'd seen it many times in photos, but in person it was elegant in design; sparkling white, perfectly proportioned. I had no idea this is what it was like inside. Here's what Wikipedia says about the fresco: "The Apotheosis of Washington is the very large fresco painted by Italian artist Constantino Brumidi in 1865 and visible through the oculus of the dome in the rotunda of the United States Capitol Building. The fresco is suspended 180 feet (55 m) above the rotunda floor and covers an area of 4,664 square feet (433.3 m2). The figures painted are up to 15 feet (4.6 m) tall and are visible from the floor below. The dome was completed in 1863, and Brumidi painted it over the course of 11 months at the end of the Civil War. He was paid $40,000 ($583,093 in 2008) for the fresco."
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