One of the biggest annual competitive horse shows is taking place in Iowa this week.

The World Percheron Congress at the Iowa State Fairgrounds runs through Saturday and is expected to draw around 20,000 visitors to Des Moines. The event only takes place in the U.S. once every four years.

Greg Edwards is the president of the Des Moines Convention and Visitors Bureau. “This is the World Series of Percheron horses,” Edwards said at press conference Tuesday. “We, that sell and market the Des Moines area, like to brag about the great things that come to our community and believe me, this is now on our top ten list and remain on that list for many years to come.”

The events are taking place in the Jacobson Exhibition Center, a new state-of-the-art indoor livestock arena which opened earlier this year on the Iowa State Fairgrounds. Fairgrounds manager Gary Slater says officials with the World Percheron Congress selected the facility two years ago. “There are other horse shows…that rival this in terms of size, so we’ll be going after those events to bring them here to the Iowa State Fairgrounds in the future,” Slater said. “But, this is the first one. This kind of puts us on the map.”

Performances that will include six-horse hitches are scheduled for 6 p.m. on Thursday, Friday and Saturday. Next year’s World Percheron Congress will be held in Normandy, France.