An estimated 15,000 thousand people, including members of Congress and Vice President Joe Biden, marched across a bridge in Selma, Alabama, Sunday, to reenact what’s known as “Bloody Sunday.” In 1965, civil rights protesters attempted to march from Selma to Montgomery but were quickly met by police billy clubs and tear gas. Bloody Sunday galvanized support for the Voting Rights Act at that time. While the commemoration is an annual event, this year's comes just days after the U.S. Supreme Court heard a challenge to a portion of the law