Photos: See Scenes of the Kentucky Derby

The Kentucky Derby, the oldest continuously held major sporting event in the United States, is celebrating its 150th anniversary on Saturday with a new $200 million paddock and a host of safety initiatives meant to curb the horse deaths that marred last year’s event.

Revelers at Churchill Downs will be wearing colorful hats and sipping $22 mint juleps from souvenir glasses under the twin spires that stand sentry over this cathedral of horse racing. From the first Derby, won by Aristides in 1875, to this year’s race, one constant has remained.

When the announcer declares, “And they’re off,” all involved with getting the top 3-year-old thoroughbreds in the country into the starting gate, from the owners to the trainers to the grooms, hold their breath and hope their horse will cross the finish line first.