If you’re not from the Midwest, you may not have heard about the annual tradition in Chicago where the Chicago River is dyed green to celebrate St. Patrick’s Day.

This year was the 55th anniversary of the river being dyed green for St. Patrick’s Day, so one YouTube’r recorded this amazing video timelapse of the river as it changes colors.

This video is certainly a bit trippy to watch! Enjoy, since everyone is Irish on St. Patrick’s Day as is told to us in the cult-classic movie, Boondock Saints.

Have a happy St. Patrick’s Day (if you haven’t already started celebrating) and be safe out there!