Brazil's characteristic jandals, of the brand Havaianas, were despised for decades as "a poor man's sandals".
However, half-a-century after the first model was launched this rubber footwear has adorned the feet of celebrities like Jennifer Aniston and Jessica Alba, among many others.
The first Havaianas came out in Brazil in 1962, with a design that was inspired by Japan's Nori sandals. Nori sandals were made with rice straw, which is why Havaianas feature to this day a rice grain design on their soles.
Given that they were cheap, these thongs were quick to storm the market among poor Brazilians.
The leap from cheap option to fashion essential came from the late 1990s, when the shoe company Sao Paulo Alpargatas sought to counter a decline in internal demand with an aggressive international marketing strategy.
The firm hired new foreign trade and international distribution personnel, it asked designers to come up with new models and it made deals with some major retailers around the world, including Harrods and Galeries Laffayette.
In 2003, French designer Jean-Paul Gaultier had his models wear jandals on the catwalk, and that same year the company presented 61 actors and actresses nominated for Academy Awards, including Jack Nicholson, Nicole Kidman and Renee Zellweger, with rubber sandals set with rubies.
From then on, Havaianas gradually grew into a global fever which, thanks to constant innovations in shape and colour, looks far from dying down. "Havaianas are a summer must-have for fashionistas," the prestigious US magazine Harper's Bazaar wrote in July.
In June, Cosmopolitan had already advised its readers to "act fast" in order to get hold of a pair of the limited-edition flip-flops Havaianas did with Italian fashion brand Missoni. They sold for US$70 (NZ$85). "These sandals do amp up any outfit in a flash," Cosmopolitan wrote.
The success that Sao Paulo Alpargatas has had in recent years made virtually true the slogan their main product has long had in Brazil: "Everyone wears them."
In fact, Havaianas now have a market share of around 80 per cent among rubber sandals in Brazil. They are sold in 80 countries and have exclusive stores in London, Paris, New York, Barcelona and Rome, among others.
"With Havaianas, we are also exporting a bit of the Brazilian way of life: joy, sun and colour," company spokesman Rui Porto told DPA.
Prices are as varied as the models. The cheapest Havaianas go for less than US$10 a pair in Brazil, while luxury models - like the 1636 pairs set with gold and diamonds that were made in 2003 - can fetch up to US$30,000.
Every year, the firm makes around 100 new models with different combinations of colour, with a view to ensuring that thongs remain "a fashion accessory that can go with any outfit, from the beach to a party, from college to a bar", according to Sao Paulo Alpargatas.
On the occasion of its 50-year anniversary, Havaianas is getting ready to launch a limited edition with 50,000 pairs of a new model.
Sales are to be fully donated to a UNICEF project to improve the quality of life of Brazilian children and teenagers.
Havaianas has also teamed up with British fashion designer Matthew Williamson to launch a special collection of colourful rain boots.
"I'm drawn to the way Havaianas capture playfulness and light-heartedness in their products - there is clearly an element of fun," Williamson told Vogue.
"I wanted to embrace this sensibility in the rain boots and so chose prints that were whimsical without being kitsch."