Conversation so far:
What was the shot heard round the world?
The home run, nicknamed the "Shot Heard 'Round the World", was dramatic as, until 1969.
What happened in 1969?
league pennants were only decided by playoff when the teams involved finished the regular season in a tie.
What happened then?
Prior to 1951 playoffs had only been necessary in 1946 (NL) and 1948 (AL).

Question: What year did the shot around the world happen?
Self-contained rewrite: What year did the "Shot Heard 'Round the World" happen?