Philadelphia's Bellevue-Stratford Hotel gained lasting notoriety during the nation's Bicentennial year.

It was then and there that the first verified outbreak of Legionnaires' Disease occurred, at the 58th state convention of the American Legion held on July 21-24, 1976. Two hundred twenty-one people were sickened by the pneumonia-like disease and 34 died, most all of them Legionnaires.

It was not until January of the following year that the Centers for Disease Control zeroed in on the cause of the outbreak: the newly-discovered Legionella bacterium, apparently spread through The Bellevue-Stratford's air conditioning system. The disease highlighted the need to keep HVAC systems clean, though Legionella can also be found in many types of water systems.

Since 1976, there have been other occurrences of Legionnaires' Disease across the world, and mysterious illnesses and deaths that happened before 1976 have been identified as being caused by the Legionella bacterium.