The UCI Cyclocross World Cup championship kicked off the second race in the series -- called the Trek CX Cup -- in Waterloo, Wisconsin this weekend before heading back overseas to Bern, Switzerland.

Racers and spectators were treated to two contrasting courses over three days. The first was a C2-classified race with dry and dusty, hard-packed lines. The second was the official World Cup race this past Sunday, and after a full day of rains and amateur racing, the world-class athletes blasted through thick layers of mud, described by the announcers at one point as "three carpets deep."

Earlier this year we said the Trek CX Cup was one of Wisconsin's best bike rides, and here are 11 images from the muddy madness that show why.

1) Kaitie Keough (front) got her start in Racine and now races on the world stage.

2) Many times it was faster to run, than to ride, especially given the risk of sliding out in the deep mud.

3) Heavy rains changed the course entirely. Some parts, even the steep hills were easier to brave on top of the bike when the course was dry. But slippery conditions and mud in the brake calipers made descents much more treacherous.

4) 15-time National Cyclocross Champion Katie Compton has had a rough time at the Wisconsin World Cup. Alergies from two years ago, a rolled tubular tire last year, and a cartoonish backslide down the run-up this year have plagued her attempts. Here she is attacking down the hill to claw back time.

5) Sunny Gilbert handles the off camber straight-aways. The higher up the hill, the drier the line.

6) Jolanda Neff started at the back of the race, but the Swiss National Road Race Champion, Swiss National Cyclocross Champion, and World Mountain Bike Champion skillfully climbed her way on to the 2nd place podium.

7) Trek Factory Hill was rideable when it was dry, but the switchback section almost nearly transformed into a footrace.

8) In dry conditions bunny-hopping the barriers is common. In the mud, the outcomes are less reliable.

9) At this point Eli Iserbyt had all but solidified his win. The constant rains transformed this little dip into a pond.

10) If you want to know what it's like to ride in these conditions, at one point the announcers called the mud "three carpets deep."

11) The short, punchy climb to the Third Space Brewing secret bar became unrideable after the rain. This photo was taken at the end of the race, with riders covered in the maximum amount of mud.

If you're looking for more check out our Trek CX Cup gallery with 27 more.

If you want another chance to race on the Trek Factory grounds, make sure to sign up for GP Jo Van Deraffe on October 19, hosted by Palomino American Cyclocross.