Thousands of people are turning out for St. Patrick's Day celebrations in Chicago this weekend.
Now in its 55th year, the annual tradition of dyeing the river draws hundreds of thousands of spectators to downtown Chicago, NBC reported.
The day itself does not fall until Friday, and Chicago was one of a few cities to kick things off early.
The dyeing of the river is still sponsored by the local plumbers union, but now they use a harmless vegetable dye to get the desired hue. The tradition started back in 1961.
'Once the orange powder hits the water, it turns a vibrant green. Bailey happened to be a childhood friend of Mayor Richard J. Daley, who wanted to centralize the various St. Patrick's Day celebrations across the city to one downtown parade.
Plumbers use an orange dye to detect leaks in building foundations and to root out illegal sewage discharges into the river.
The exact formula is a closely guarded secret, but it has been tested and is safe for the environment.
The Chicago River was dyed a bright green color on Saturday, kicking off a weekend of festivities. The parade was scheduled to begin at 12 noon CST.
This year's incarnation of the parade in Chicago was expected to feature the regular fare of people playing bagpipes, performing traditional Irish dances, floats and marching bands playing as local politicians walk along.