On this day, 150 years ago, Abraham Lincoln delivered his famous speech, The Gettysburg Address.

Most Americans older than the age of 7 can recite the starting line of Lincoln's famous speech: "Four score and seven years ago" — but what does that even mean? And what else did Lincoln have to say in his famous speech in 1863?

Filmmaker Ken Burns is encouraging folks to take a closer look at the Gettysburg Address with his new project, Learn the Address. Burns asked a number of notables, including all of the living American presidents, as well as celebrities such as Taylor Swift, Usher, Steven Spielberg, Uma Thurman, Stephen Colbert, Bill O’Reilly and Gabrielle Giffords — to recite Lincoln's famous speech. And he's asking everyone in America to do the same and upload videos of themselves to the Learn the Address website to share the experience.

“It’s a complicated country with lots of points of view,” Burns said in an interview with the New York Times, “but there is some glue that still holds us together and some of that glue begins ‘Four score and seven years ago.’” He added, “When you do things in unison, you feel a little better.”

Burns' project was inspired by his new film, "The Address," which will air on PBS in April. 

Take a look at a snippet in this interview with Burns on MSNBC:

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Mark 150th anniversary of Gettysburg Address by reciting your own version
Add your video to others compiled by filmmaker Ken Burns — from Bill Clinton to Bill Gates to Whoopi Goldberg.