Flashback to May 17, 1954: Brown v. Board of Education is decided by the United States Supreme Court, which said that it was unconstitutional to have racially segregated schools. Flash-forward to Montgomery County High School, Georgia, 2009: A school holds separate proms for black and white students.

Timed for the 61st anniversary of Brown v. Board of Education, director/cinematographer Gillian Laub takes us to the small town of Mount Vernon, where they've only just begun to have desegregated proms. Her film, "Southern Rites," is named after the book of the same name she wrote after studying the town's racially divided homecoming and proms for 12 years.

"Southern Rites" takes a look at the complicated race relations that persist in the town just one year after the high school's first desegregated prom. Check out the clip below, courtesy of HBO:

Laub's no stranger to the town of Mount Vernon -- her 2009 essay, "A Prom Divided," which was published in The New York Times Magazine, sparked such outrage it caused the school to finally desegregate the proms.

John Legend, who is an executive producer on the project, discussed his thoughts about the situation in Mont Vernon. "I was so mystified how this could still be happening in the 21st century," he said in a clip from HBO.

"Southern Rites" premieres Monday, May 18 at 9 p.m. ET on on HBO.