 In the late 1990s, the Penitentiary Glen Nature Center began a nostalgic Halle's 7th Floor Holiday Memories Exhibit including a re-creation of Mr. Jingeling's seventh-floor castle from 1956.When Keyes visited the exhibit in 1999, he was recognized by fans who formed a long line to get his autograph.Keyes died of congestive heart failure the day after Christmas in 2000.