WASHINGTON - As the nation's economy was still reeling from the body blow of the Great Recession, Seattle's was about to take off. In 2010, Amazon opened a headquarters in the little-known South Lake Union district - and then expanded eightfold over the next seven years to fill 36 buildings. Everywhere you look, there are signs of a thriving city: Building cranes looming over streets, hotels crammed with business travelers, tony restaurants filled with diners. Seattle is among a fistful of cities that have flourished in the 10 years since the Great Recession officially began in December 2007, even while most other large cities - and sizable swaths of rural America - have managed only modest recoveries.