House Minority Leader Hakeem Jeffries (D-N.Y.), Rep. Maxine Waters (D-Calif.), Rev. Al Sharpton, Rep. Jonathan Jackson (D-Ill.), the son of civil rights icon the Rev. Jesse Jackson, walk across Edmund Pettus Bridge as they commemorate the 60th anniversary of "Bloody Sunday" in Selma, Alabama, on March 9. Photo: Michael M. Santiago/Getty Images

The population of the small historic town of Selma, Alabama swells once a year as people from around the nation flock to its downtown, its churches before finally gathering for the crescendo event -- walking across the Edmund Pettus Bridge.

Selma on Sunday marked the 60th anniversary of the clash that became known as Bloody Sunday. The attack shocked the nation and galvanized support for the U.S. Voting Rights Act of 1965.