Chicago River to be dyed green for St. Patrick's Day

The Chicago River will be dyed a bright shade of emerald green on Saturday, kicking off the city's St. Patrick's Day festivities.

Thousands of people will line the riverfront downtown to see the dyeing, a tradition for the holiday that dates to 1962.

The Chicago Plumbers Union started the tradition of dyeing the river green, with a material once used to locate leaks in buildings. Organizers say the powder used is a secret recipe and is environmentally safe.

The Associated Press contributed to this story.