St. Patrick’s Day falls on a Tuesday this year, which means some of the major celebrations of the holiday took place over the weekend.
For the Windy City, that meant Saturday was the day that the Chicago River went green, an annual tradition that dates back to 1962.
The dyeing takes about five hours and involves 40 lbs. of powdered green vegetable dye going overboard from a boat as it navigates the river. (The video is soundtracked – as virtually all St. Paddy’s day-themed videos must be – to an old Irish fiddle tune called the “Kesh Jig” – you may recognize it as the basis for Flogging Molly’s “Salty Dog.”).
“You don’t have to be Irish to enjoy this,” Katherine Malhas, who was named St. Patrick’s Day Queen in 1970, told the Chicago Tribune. “It’s a Chicago city celebration.”
And it just wouldn’t be St. Patrick’s Day without it.
This article originally appeared on People.com.
Read next: How America Invented St. Patrick’s Day
More Must-Reads From TIME
- Jane Fonda Champions Climate Action for Every Generation
- Biden’s Campaign Is In Trouble. Will the Turnaround Plan Work?
- Why We're Spending So Much Money Now
- The Financial Influencers Women Actually Want to Listen To
- Breaker Sunny Choi Is Heading to Paris
- Why TV Can’t Stop Making Silly Shows About Lady Journalists
- The Case for Wearing Shoes in the House
- Want Weekly Recs on What to Watch, Read, and More? Sign Up for Worth Your Time
Contact us at letters@time.com