Happy International Women’s Day 2018! What’s the theme this year and what is the history behind the day?

INTERNATIONAL Women's Day celebrates the achievements of women, as well as acting as a catalyst for change when it comes to gender equality.

It has been observed for over 100 years and is now marked around the world. Here's everything you need to know.

When is International Women's Day 2018 and what is the theme this year?

International Women's Day falls on March 8 every year - that means that it falls on Thursday this week.

The day brings together global governments, women's organisations, businesses and charities together under the banner of International Women's Day.

The day itself will be marked with talks, performances, rallies, networking events and marches.

With the recent scandals in Hollywood, and the World Economic Forums' Global Gender Gap Report showing that it will take 217 years to close the gender parity gap, it's more important than ever that aim for progress.

The theme of this year's International Women's Day is #PressforProgress.

The website argues: "We can't be complacent. Now, more than ever, there's a strong call-to-action to press forward and progress gender parity.

"A strong call to #PressforProgress. A strong call to motivate and unite friends, colleagues and whole communities to think, act and be gender inclusive."

What are International Women's Day's origins?
The earliest observance of a Woman's Day was held in New York on February 28, 1909, and was organised by the Socialist Party of America.

A year later, at the International Women's Conference in Copenhagen, Socialist representatives proposed that there be an International Women's Day, inspired by the demonstration in New York.

The delegates agreed that an international day should be formed as part of a strategy to promote equal rights for women and women's suffrage.

It was celebrated for the first time in Austria, Denmark, Germany and Switzerland on March 19, 1911.

Two years later, in 1913, it was proposed that the date be moved to March 8 and it has been celebrated on this day ever since.

Why do we still celebrate International Women's Day?
The original aim of International Women's Day was to achieve gender equality for women - this has not yet been realised.

The Gender Pay Gap still exists in the UK where women earn up to 14% less than men. In January 2018, Ladbrokes, EasyJet and Virgin Money revealed pay gaps of over 15% in favour of men.

This story is told around the world for a number of reasons, including the lack of women's representation in politics and business.

The World Economic Forum found in 2017 that at the current rate of progress the global gender gap will take 100 years to close.

This represents quite the decline over 2016 where it was estimated to be 83 years.

Last year also saw the rise of the #metoo movement where women from all over the world came forward to share their story of sexually harassment.

The women who broke their silence on sexual assault and harassment were named Time's Person of the Year - The Silence Breakers.