Saturday will mark 20 years since nearly 3,000 Americans, including 496 Long Islanders, were killed in one of the darkest days in United States history.

Americans were left mourning 2,977 lives and their sense of security after four United States commercial flights bound for the West Coast were hijacked.

Then-President George W. Bush addressed the nation of the tragedy that reduced New York City’s twin towers to rubble.

“I can hear you, the rest of the world hears you, and the people who knocked these buildings down will hear all of us soon,” Bush said.

Now the Freedom Tower stands at 1,776 feet as a reminder of the enduring promise and resilience of the country.

Mayor Bill de Blasio says the city still feels the day intensely 20 years later.

“This wound will never entirely heal,” de Blasio said.