SAN DIEGO -- The oldest living recipient of the Congressional Medal of Honor will serve as the grand marshal of San Diego's 30th annual St. Patrick's Day parade Saturday.

Retired Navy Lt. John Finn, who is 100 years old, was awarded the medal for heroism and distinguished service during the Japanese attack on Pearl Harbor on Dec. 7, 1941.

He will be joined in the procession down Sixth Avenue by other veterans of World War II, the Korean War, the Vietnam War and the wars in the Persian Gulf.

The theme of the parade, which is scheduled to start at 11 a.m., is "Celebrating 30 Years of Community Unity with Special Thanks to our Veterans and Military."

More than 50,000 people are expected to watch the parade, which will also feature five marching bands, three bagpipe contingents, dancing groups, representatives from Ireland, roller skaters, antique cars, clowns, the reigning "Miss Colleen" and the winner of a "Smiling Irishman" contest.

Coinciding with the parade is a free festival, which runs from 10:30 a.m. to 6 p.m. along the west side of Balboa Park. There will be two stages with entertainment, two beer gardens, Irish food, a kids zone and a mock Celtic village.