Seattle's South Lake Union deserves a mention
Historically, this area was an industrial and dockyard district, equivalent to the meatpacking district, or the hudson side of chelsea. So despite being geographically close to downtown, it was a completely separate area with separate people and activities. At one point Henry Ford built the first Ford factory west of the mississippi here.
Anyway, Seattle's downtown never experienced a serious decline like St. Louis or Detroit, but South Lake Union did. The containerization of shipping in the 60s eliminated 99% of the labor involved in maritime logistics, and by 1970, pretty much all the dockyards and warehouses were decaying and abandoned.
As you can see in the photo below, the city's response was to convert conndemned buildings into surface parking.
Here is the area in 1970 and 2015:
And the redevelopment is still ongoing. Here are a bunch of empty lots in 2016, and what they are now (via google earth). there is only one empty block left