On a Tuesday morning 20 years ago the lives of North American residents and travellers worldwide changed forever.
For many, the plane hijackings and the attacks on the World Trade Center's twin towers and the Pentagon left indelible memories.
Tell us where you were, what you experienced, how you recall the 9/11 attacks and their aftermath.
Send us your reminisces via email to editor@niagaranow.com or on our Facebook page.
We'll compile some of your memories and recollections as we mark two decades since another day that lives in infamy.