None of the panoramas were 3 miles long, although that was claimed in the
advertisements for them. This kind of Panorama was a very much American
event at the time. They were a fad for decades during the middle of the
(last) century, and performances did end somewhat abruptly in the 70ies
(dunno why, though). That was long before the moving pictures (cinema)
became popular. A history of some of these panoramas is to be found in
John F. McDermott's _The Lost Panoramas of the Mississippi_, Chicago:UCP
1958.