Last year marked the 50th anniversary of the Freedom Rides, in which some 400 black and white Americans defied racist mobs and institutional bigotry to desegregate the South’s bus lines. John Lewis, then a 22-year-old student at Nashville’s American Baptist College, was one of the initial 13 riders — and for his trouble, he was attacked by thugs and their Klansman ringleader at a bus terminal in Rock Hill, S.C., and bloodied. Today, for his role in the Freedom Rides as well as the sit-ins that defied the segregation of Nashville’s downtown lunch counters, Lewis is revered as one of the heroes of the civil rights movement. He’ll give the keynote address today at Vanderbilt’s commemoration of Dr. Martin Luther King Jr. Day, as part of a ceremony that includes performances by Vanderbilt student groups Voices of Praise, Victory A Cappella, Jeremiah Generation and the Blair Chamber Choir. The event also includes readings by winners of a Nashville student essay contest: congratulations to Chelsea Walker (Hume-Fogg), Israel Tovar (Hume-Fogg), Gabrielle Depalo (Bellevue Middle School) and Elizabeth Kimbrough (Overbrook). The event is free and open to the public, but tickets must be obtained in advance at the box office in Sarratt Student Center.