50 years ago in Expo history: ‘Transient youths’ were expected to visit the fair without much trouble, though a small amount could be ‘dissidents’

Also on this day

(From onthisday.com)

1781: 1781 William Herschel sees what he thinks is a “comet” but is actually the discovery of the planet Uranus.

1930: Clyde Tombaugh announces discovery of Pluto at Lowell Observatory