Original sentence: Director Steven Spielberg heard about some of the letters, and several were included in Spielberg's short documentary The Unfinished Journey (which screened in front of the Lincoln Memorial on the National Mall on December 31, 1999, as part of the millennial celebrations)
Edited sentence: , on December 31, 1999, as part of the millennial celebrations).Director Steven Spielberg heard about some of the letters, and several were included in Spielberg's short documentary The Unfinished Journey (which screened in front of the Lincoln Memorial on the National Mall in Washington, D