a moment when the course of events is changed

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“Affect” vs. “Effect”: Use The Correct Word Every Time
The Meaning Of Labor Day

Americans’ identities are shaped by shared experiences — and there are a handful of historically significant experiences that stand out above the rest.
Since the survey was conducted over a year ago, the responses don’t account for more recent events like President Donald Trump’s inauguration, mass shootings in Las Vegas and Parkland, or the #MeToo movement.

The Administrator,
Schumacher College,
The Old Postern, Dartington, Totnes,
Devon, TQ9 6EA, UK
Schumacher College is one of the learning institutions that are part of the Dartington Trust, a company limited by guarantee, registered in England and as a charity
(company no. 1485560, charity no. 279756).
Registered office: The Elmhirst Centre, Dartington Hall, Totnes, Devon TQ9 6EL, United Kingdom

References:

http://www.thesaurus.com/browse/life-changing
http://www.businessinsider.com/americans-name-the-top-10-historic-events-that-shaped-their-lifetimes-2016-12
http://www.schumachercollege.org.uk/courses/short-courses/changing-the-frame
http://www.careerjet.com.au/teachers-on-net-jobs.html