Seattle is a major port city that has a history of boom and bust. Seattle has on several occasions been sent into severe decline, but has typically used those periods to successfully rebuild infrastructure. There have been at least five such cycles:
The lumber-industry boom, followed by the construction of an Olmsted-designed park system.
The Klondike gold rush started in 1896, but reached Seattle in July 1897. This constituted the largest boom for Seattle proportional to the city's size at the time, and ended the economic woes Seattle (and the nation) had been suffering since the Panic of 1893.
The shipbuilding boom, which peaked during World War I and crashed immediately thereafter, followed by the unused city development plan of Virgil Bogue.
The Boeing boom, followed by general infrastructure building.