The Sept. 11, 2001, terrorist attacks were such a unifying event for modern Americans, and nothing else has come close to being as important or as memorable, according to a new survey conducted by Pew Research Center.

Roughly three-quarters (76%) of the public include the Sept. 11 terror attacks as one of the 10 events during their lifetime with the greatest impact on the country, according to a national online survey of 2,025 adults conducted June 16-July 4, 2016.