Designers, celebrities and shoppers in cities from New York to Milan roamed boutiques and stores in droves on as part of the fourth annual “Fashion's Night Out,” a global event to encourage spending.

The event, held on the first night of the semi-annual Mercedes-Benz Fashion Week in New York, is the brainchild of Vogue magazine editor Anna Wintour and was designed to jump-start an industry battered by the global recession in 2009.

“Fashion's Night Out,” has since turned into a global night of retail revelry in 19 countries, according to organizers, as store stay open late and offer drinks, entertainment and free products to the throngs.

“We come out to see everybody and what they're wearing. Every year (the stores) are trying to do something bigger and better and it's cool to see.... It's the buzz of the city,” said Brittany Wolf, 24, who helps branding for an accessories line, Theodora & Callum, in New York.

In New York, the night was expected to attract tens of thousands to the approximately 900 stores, said George Fertitta, head of NYC & Company, the city's official marketing and tourism organization.

In Paris, thousands converged on the city's the 8th district, blocking traffic for several hours on two boutique-studded avenues. The center of Milan was also packed with potential shoppers, many of them students, sipping from plastic glasses of free cocktails dispensed by nearby boutiques.

In London, about 400 stores were participating, according to a spokesperson with Conde Nast, the giant high-end magazine publisher that owns Vogue. Sydney's night out had over 600 retailers participating, with some offering products only on sale that night, Vogue Australia said on its website.

The extra publicity the night can bring to stores and designer brands is as important as getting customers out to the stores, Fertitta said.

Bloomingdale's flagship department store in New York, featured members of the band Matchbox Twenty, hip-hop artist and designer Pharrell Williams, and actor Kellan Lutz from the “Twilight Saga” films.

At Colette, a clothing and accessories boutique in Paris, celebrity stylist David Mallet applied hair extensions for shoppers while at Chloe, nearby, customers watched a cheerleader show with editor-in-chief of Vogue's French edition, Emmanuelle Alt.

“(The stores) compete with each other ... in terms of who is going to be most exciting, who is going to most fun, who is going out be most interesting,” Fertitta said.