The errant antiaircraft round gouged the building in 1942. The gold Mylar confetti fluttered to the roof during the year 2000 festivities. The cracks in the huge marble blocks formed when the 2011 earthquake shook the massive structure. For almost a century the timeless Lincoln Memorial has stood exposed to the sun, wind and rain as Washington changed around it and marked it with evidence of the passage of time. Now it is getting a $25 million top-to-bottom makeover, and Thursday the National Park Service provided a glimpse of how the project is going and showed some of the work that has to be done.