This year's parade theme is 250 years of Irish contributions to America.

PHILADELPHIA (WPVI) -- The City of Philadelphia turned several shades of green Sunday as crowds gathered for the annual Philadelphia St. Patrick's Day Parade.
Spectators lined the streets to celebrate Irish culture and heritage. The theme this year is 250 years of Irish contributions to America.
Security was enhanced this year due to the war, and because Ireland's Prime Minister marched in the parade.
He's here today to celebrate Irish contributions to America, ahead of our nation's 250th birthday.
Generations of Irish have emigrated to Philadelphia.
The parade stepped off at 11:15 a.m. at 16th Street and JFK Boulevard, traveled through Center City, and wrapped up on Market Street between 6th and 5th streets.
Along the route, paradegoers watched colorful floats, Irish dancers, performances, marching bands, and plenty of Irish spirit.
For the full list of road closures and information about transportation, click here.