An estimated 250,000 people are in Shelbyville, Tennessee, for the annual Tennessee Walking Horse National Celebration, which began early today (NZ time).
There are 11 days of competition, culminating in the announcement of the new world grand champion on September 5.
The event has been held annually since 1939.
Tens of thousands of fans gather to watch the many classes in which the horses show off their distinctive gait.
The celebration opened amid recent revelations that three times as many violations for soring - the controversial practice of irritating horses' legs in order to have the animals exaggerate their gait - were found by authorities this spring and summer compared to the same time last year.
However, the results do not reflect an increase in soring, but better testing methods.
Also, the first lifetime suspensions have been handed out for violations.
Horse industry leaders will be meeting during the Celebration to discuss the future, and how to combat both soring and negative perceptions generated about the Walking Horse show industry.