Original 1970 advertisement commemorating the Japan World Exposition, Osaka, 1970 or "Expo '70," the world's fair held in Suita, Osaka Prefecture, Japan between March 15 and September 13, 1970.  Its theme was "Progress and Harmony for Mankind."
 
Seiko was the official Expo '70 timekeeper, advertizing that its atomic clock was so precise it would take "more than a thousand years" for it to be more than one second off.  Seiko set up the clock to  simultaneously direct 110 other clocks in 50 different sites throughout the exposition site.
 
Dimensions: 10.25 inches wide by 13.5 inches high