The Kentucky Derby is not just a sporting event.

It's a downright party for the better part of a week, culminating with the Run for the Roses on Saturday.

The "fastest two minutes in sports" is a thrill from start to finish, and a three-year-old horse and their team, from jockeys to trainers to owners, have invested millions of dollars to make sure their horse is in prime condition.

The $3.1 million paycheck for crossing the finish line first at the 1 1⁄4 mile track at Churchill Downs in Louisville, Kentucky, is another reason for the event's excitement.

But beyond the pomp and circumstance, the nearly 150,000 spectators who attend the Derby every year have turned the race into a style event, complete with colorful wardrobes, outrageously large hats, and nothing saying more than a lack of interest in the actual race than posing with a partially drank mint julep, a Derby staple for more than a century.

Kentucky Derby hats and style

The first Kentucky Derby was run on May 17, 1875, and while the actual horse race is the ultimate money maker, the event's style quickly became a focus, thanks to a relative of America's most famous explorers.

The Derby was founded by Meriwether Lewis Clark Jr., the grandson of William Clark, who led the Lewis and Clark Expedition, part of the exploration to the western United States.

According to the Kentucky Derby Museum, Clark Jr, especially when it came down to female fashion, "envisioned a racing environment that would feel comfortable and luxurious, an event that would remind people of European horse racing."

Over time, style took center stage as men wore suits to the race and women added accessories to their outfits, including gloves, hats, and parasols to top off their look.

Today, outfits seem to become more colorful and sometimes outlandish, with women's expansive hats garnering attention during the pre-race festivities.

This article originally appeared on USA TODAY: How the Kentucky Derby became one of America’s premier style events