June 20, 1959 - Winnipeg is the first community in North America to create a single emergency number: 999. It was based on London's system that began in the 1930’s.
999 Switchboard ca. 1969 (source)
The number was changed to 911 in 1972 just prior to other cities in North America rolling out the same service. (See CBC Archives' Winnipegers call 999 for help.)
June 20, 1922 - Frank Oliver Fowler is elected 33rd Mayor of Winnipeg in a by-election following the June 1922 death of Edward Parnell in office earlier in June.