Indeed, the entire Bellevue building at Broad and Walnut streets in Philadelphia was at one time the Grandest Hotel in Philly. Then came the tragic Legionnaires convention where many of the guests died due to some kind of mold-based virus spread through the ventillation. That was the 70's. The building was shut down and left to rot until the mid 80's sometime when it was fully gutted and refurbished. Floors 1 thru 11 are offices and shopping. There is a nice food court in the ground level, along with Zanzabar Blue - a famous Philadelphia Jazz bar. On the street level is the Palm Restaurant - a great steak house.
Floors 12-18 became "The Hotel Atop the Bellevue" when the building reopened in the 80's. On the 19th floor were the Barrymore room and Founder's Restaurant. The hotel check-in was also located here. Sitting in the Barrymore room or Founder's was (and still is) an awesome experience with the high domed ceiling. Watch what you say, though, because the person 40 feet across the room might here even your slightest whisper.
In December 1996, Hyatt took over the hotel, branding it one of their Park properties. They tried to maintain as much of the elegance and class that had become the "new" Bellevue's hotel reputation. I'd have to say they did a pretty good job. The one thing I was disappointed to see was that the Barrymore room was completely rennovated to be a big lobby for the hotel check-in. It used to have cafe/cocktail tables and nightly entertainment under the prior management. Founder's is still there and remains one of Philly's top restaurants.
There are a total of 170 rooms on floors 12-17(maybe even 11, though I'm not completely sure). You enter through the street entrance and take the elevator to 19(top floor) to check-in, and then take a different elevator down to your room.
You'll enjoy it plenty. If you like Jazz, get reservations at Zanzabar. You won't even have to leave the property in the cold of winter, since it's an elevator ride down to the ground level.
If you like good orchestra music, get tix to the Philadelphia Orchestra at the brand new Kimmel center(www.kimmelcenter.org) just 2 blocks down the street. It's an absolutely fantastic venue with perfect accoustics. Just opened in December 2001.