Park Hyatt Philadelphia at the Bellevue
During the Bicentennial, this place played host to an American Legion convention that left more than 200 legionnaires sick with pneumonia-esque symptoms, and ultimately 34 of them dead.
After closing/investigating the hotel, they discovered a new strain of bacteria in the cooling tower and named the fatal respiratory condition it caused Legionnaire's Disease. It's now owned by Hyatt, who swear they have not killed a single legionnaire yet.
Park Hyatt Philadelphia at the Bellevue
200 South Broad Street
Philadelphia, Pennsylvania, USA, 19102