20,000 maggots gathered at Water Works Park in Des Moines, IA on Saturday to celebrate the 25th anniversary of Slipknot‘s debut album at Knotfest Iowa.

Parking lots opened around 8AM, 13 hours before Slipknot was scheduled to hit the stage, but fans arrived early so they could get in line and secure a spot on the barricade where they would stand all day. Prior to Slipknot’s set, the main stage was graced by newcomers Holy Wars, Zulu, and Vended as well as heavy hitters like Hatebreed, Knocked Loose, and Till Lindemann (Rammstein).

The second stage featured performances by Des Moines natives DOSE as well as bands like Twin Temple, Dying Wish, and GWAR, among others. Fans started at the main stage and made their way to the second stage in between sets to make sure they didn’t miss any of the action.

Just after 6PM, it was announced that set times would be moving due to severe weather entering the area. Slipknot ended up going on an hour early at 8PM and the moment they stepped on stage it started raining. There was something really chaotic and special about seeing them in the rain with lightening in the background. Yes, their set got cut short be a couple songs, but the storm enhanced the experience.

Check out photos from the main stage below!