Mack kept its headquarters in Allentown for over a century, and the museum it founded in 1984 kept the paperwork: build records, service and parts information, engineering drawings, the original bulldog. On the floor sit a 1909 Mack Brothers bus, a row of experimental rigs, and the Megatron prop from Transformers: Dark of the Moon. Tours are guided, by booking, on Mondays, Wednesdays and Fridays.