International Women's Day is also 'Women's Pay Day' according to the UK's Trades Union Congress. It says March 8 is the day when average women effectively start earning, compared to better paid average men.
Working for free.
That is effectively what women in the UK have been doing so far this year because of the country's gender pay gap.
Because they are paid less, only now does the average woman start earning compared to the average man, according to Britain's Trades Union Congress.
On International Women's Day, it is a bitter pill to swallow.
"It is a big let down for women in this country because it is 100 years since some women got the vote, not all women," TUC Policy and Campaigns Officer Ines Lage told Euronews.
"But it is still 100 years. Generations have passed since we have seen women go out onto the streets and demand equality, a voice."
Some might see irony in the fact that Britain has its second female prime minister, Conservative Theresa May.
"We would like to see a female prime minister be bold in addressing the gender pay gap that is so wide as the UK's," Lage said.
Figures just released by the European Union's statistics agency, Eurostat, show that women in the bloc earned, on average, 16 percent less than men in 2016.
The UK had the fourth highest pay gap behind Estonia, the Czech Republic and Germany.
Setting a better example, with a much smaller gap between men and women, were Romania, Italy and Luxembourg.
Women have made a big impact in the world of work, in London and across the United Kingdom.
But the gender pay gap figures show there is still a long way to go.