From 1866 to 1966, this site was occupied by the Elgin National Watch Company, the first watch factory built west of the Alleghenies, which grew to become the world's largest. During its lifetime, more than 60 million Elgin watches were manufactured here. The building featured a 144-foot-tall clock tower with dials whose numerals were three feet in length, a foot longer than those of London's Big Ben. Nearby stood an observatory built for astronomical time determination before the advent of national standards, and that observatory is now used as a planetarium by School District U-46.