In Mississippi, lawmakers celebrated International Women's Day by passing the most restrictive abortion law in the US. In Spain, women celebrated the occasion by embarking on an "unprecedented" strike that saw millions of women flood the streets in towns and cities across the country, shouting their slogan: "Without us, the world stops."

Women organized walkouts at their workplaces, with some demonstrations lasting up to 24 hours.

Two leading trade unions, the CCOO and UGT, said that by lunchtime the strike had snowballed into a "great success", with 5.3 million women across the country joining the first of three two-hour work stoppages.

In Madrid, 80% of workplaces were observing the strike, they said after a picket at the doors of the city hall in Plaza Cibeles, according to the Telegraph.

Demonstrators - which included men and women - marked the start of the strike at midnight on Wednesday with a traditional cacerolazo: The collective banging of pots and pans to create a hellish racket.

Strikers even briefly blocked some of Madrid's chief traffic routes during rush hour. In one of the few outbreaks of violence, four dumpsters near Madrid's Complutense University were set on fire.

In Barcelona, groups of women blockaded several roads, with around 30 protesters blocking Gran Via, the city's main road for an hour before they were removed by police.

As AFP explained, 10 unions called the strike to demand gender equality in compensation. It was meant to be a 24-hour strike. Famous female television broadcasters remained absent from radio or television.

Organizers also urged women not to spend money - and to avoid products like deodorant that typically cost more for the feminine version. The CCOO and UGT didn't participate in the 24 hour strike, but rather organized strike windows for workers to stop working. The strike was meant to imitate Iceland's 1975 work shutdown, when women took a day off in October of that year to demonstrate their vital contribution to the economy.

Pilar Lahoz, a 35-year-old office worker who carried a sign that read "Without us the world stops" in Madrid, told AFP that she has struggled to change jobs because potential employers rule her out when she says she is planning on having children.

"While we have advanced a great deal there is still much to do," she said.

According to Eurostat, Spanish women earn 14.9% less than Spanish men.

Powerful politicians, including Deputy Prime Minister Soraya Saenz de Santamaria spoke of the discrimination they've endured: "There are still many things that need changing because even as deputy prime minister you experience unacceptable sexist behaviour."

Famous actresses like Penelope Cruz and Rossy de Palma joined in the strike, with Cruz drawing attention for letting her partner Javier Bardem take care of their two children while she joined the demonstration.