River green for St Patrick's Day
The Chicago River is glowing a bright emerald green as the city kicks off its St Patrick's Day celebrations.
Thousands of cheering onlookers clustered along bridges as members of Chicago Journeymen Plumbers Union Local 130 began dumping containers of dye into the river from motorboats.
The annual tradition began at 9.30am local time and immediately precedes the St Patrick's Day parade.
The union has done the dyeing since 1962. Organisers had feared that large chunks of ice would impede the process, but recent warm temperatures kept the river clear.
The hue typically lasts about six to 12 hours.
The parade route winds through central Chicago and ends at the landmark Buckingham Fountain. A second parade on the city's South Side is taking place on Sunday.