Photograph by Ray Cranbourne, The Sun News-Pictorial

On this day in 1965, a beautiful, bold, bare-legged British model shocked the world. Jean Shrimpton, one of the first supermodels, showed up at Flemington Racecourse in Melbourne, Australia on Derby Day wearing a dress four inches above the knee to the mortification of the conservative crowd.

There was absolute silence in the lounge at Flemington when Shrimpton arrived accompanied by her boyfriend, actor Terence Stamp. She was openly scorned by the horse race fans for defying protocol by not wearing a hat, stockings or gloves. In the stands, she was met by catcalls from men and jeers from women. She was surrounded by kneeling cameramen shooting from below to make the dress look even shorter.

Australia’s The Sun News-Pictorial newspaper dumped the Derby and its winner from the front page for the story on Shrimpton’s outfit. Radio and television stations and newspapers published editorials against the outfit, and Shrimpton defended it:

“I don’t see what was wrong with the way I looked. I wouldn’t have dressed differently for a race meeting anywhere in the world.”

Under pressure by her sponsors, three days later, Shrimpton arrived at the Melbourne Cup Day dressed and accessorized in a three-piece grey suit, straw hat, beige gloves and stockings, and a brown handbag.

Shrimpton’s appearance at Derby Day 1965 was the introduction of the miniskirt to most of the planet, although London designer Mary Quant had promoted it the year before. Shrimpton’s Derby Day appearance was the moment when a global youth culture began to shape young people’s style of dress. Girls wanted to be like “The Shrimp”: free and cool.

The dress was made by Shrimpton’s favorite designer, Colin Rolfe. It was a simple white shift dress. There was not enough of the chosen fabric to complete his design, so at Shrimpton’s suggestion, Rolfe improvised by finishing the hemline a daring 4 inches above the knee. Shrimpton told Rolfe: “Nobody’s going to take any notice…” She told the press: “I always wear my day dresses above the knee.”

“Youthquake” was how it was dubbed by legendary Vogue Magazine editor Diana Vreeland.