In FWWM, the scenes at FBI headquarters in Philadelphia were actually filmed at the former Cabrini Hospital building in Seattle, WA. Much to my dismay, the building was razed in 1995 to make way for cheaply built, crappy new condos. Ugh. Below, a vintage postcard of the building in its heyday which I've marked to show you where they filmed. Next to that, I've attached an excerpt from the Seattle Times mentioning the shoot.

After years of questions about this location, and hours upon hours of scouring Seattle's neighborhoods on Google Maps, I finally located the building seen outside Coop's window. Since I didn't see any buildings around it on Google with matching bay windows (like the ones behind each desk in the FWWM) there was much confusion when I actually went to this area because (as I later found out) the building they shot in wasn't there anymore.

In 1995, the Cabrini Hospital was leveled. Below, a photo of the last remaining floor of the hospital during demolition, followed by a shot of the dumb-ass building that's there now.

Some screen captures of the FBI office scenes from FWWM. So sad that it's all gone.Forever. :(

example) P.S. Why is a tiny sliver of my text being cut off on the left side? That's really annoying.