In early 2012, I was groped on a bus in London. I was vocal about it and made sure everyone around me heard what had happened. Every other passenger looked out of the window.

Soon after, on 16 April 2012, I started a simple website where I asked people to share their experiences of gender inequality. Today, just three years on, 100,000 testimonies have been submitted to the Everyday Sexism Project from around the globe. They describe humiliation and harassment, prejudice and discrimination, domestic violence and rape. These stories have been used to work with ministers and parliamentarians in various countries; to teach about consent and healthy relationships at schools; to help police forces improve their response to sexual offences; and to tackle workplace discrimination in businesses.

Among the 100,000 stories submitted, near-identical experiences emerge again and again. Stories of women being masturbated at in public spaces came in their thousands, from Spain to Turkey, Germany to India. Women in Japan, England and Israel were told not to bother with higher education as it was their sole destiny to become homemakers for their future husbands. A woman was grabbed between the legs in a souk in Morocco and another had her crotch groped in a nightclub in China. A woman in North Africa was demoted by her boss for refusing his requests for sex, and an employee in Europe was sacked when she turned down her superior’s offer of a threesome.

Experiences shared by men and boys, such as being ridiculed for asking for parental leave, or suffering homophobic bullying for trying to stand up to lad culture, revealed the damage gender stereotypes do, not just to women, but to everybody.

The stories came from people aged eight to 80, be they wearing hijabs or bikinis, about sexism on aeroplanes and trams, at home, work and school. You can trace an entire lifetime of gender inequality through the experiences women have shared through the project …

It starts young. At 11 or 12 you begin to experience harassment …

I was 12, walking home after school, when a white van full of builders drove past honking and doing sexual hand gestures and shaking their heads with their tongues out.

When you make it to school, the sexism continues …

I’m 11 and I’ve just started high school. I’m constantly told by my peers and even my best friend that women should really just stay in the kitchen and clean so that guys can have a decent meal when they get home from work. They also make jokes about me and my friends being sluts and whores because we have breasts.

Even within your family or an intimate relationship you may not escape sexism and violence …

I was raped by my father as a child. When I first told this to someone I felt comfortable with, my current boyfriend, he made a rape joke and said: “Well, you shouldn’t have led him on.”

When you reach university, you are bombarded with harassment and even assault on and off campus …

In the nine months I’ve been at university, I’ve been almost raped, thrown against a wall for refusing to make out with a guy, threatened (“I’m going to fucking kill you, bitch”) for standing up to a man sexually harassing my friend, and groped or touched without consent on about 75% of nights out. I’m sick of this.

You graduate to a pay gap, and a workplace rife with sexism and harassment …

I was told by my boss and his boss that they prefer not to work with women. Many men used foul language deliberately to put me off working with them. I was paid less than male colleagues I managed.

When you choose to start a family, you risk losing your job because of maternity discrimination …

I was brought into a company based on close to a decade worth of experience in my field. I then brought on nearly 10 other highly experienced individuals. I had several former clients who loved me and loved my work … I was fired for being pregnant.

On your way to and from work, you pass through public spaces which can be unsafe …

Guys have grabbed my butt while I was walking on the street minding my own business, my crotch too ... I constantly hear guys making comments about me, I am beeped on the street and I am shouted at with what they might see as “compliments”. The last time a guy harassed me he said: “I would tear apart your ass.”

Facebook Twitter Pinterest Inequality is everywhere. Photograph: Leon Neal/AFP/Getty Images

You walk past billboards and buses and magazine stands conveying an artificial ideal to which you are constantly compared …

I don’t have the giant boobs all the girls on the fronts of the magazines have. I don’t have the giant boobs and the perfectly toned ass that all the girls in the music videos have ... I don’t have a little nose or perfectly straight white teeth. I don’t have a flawless airbrushed complexion like every single woman on any of the multiple face cream/makeup/toiletries/whatever else adverts I see every day. I have small boobs, some cellulite on my thighs, a kinda big nose, slightly wonky teeth and some facial scars from a car accident a few years ago. And I feel ridiculous. I feel that because of all these things I’m not worth anything as a human being.

The sexism you face might combine with other forms of prejudice …

I overheard someone ask my boyfriend: “What’s f***ing a Paki like?”

Yet while all this is happening, other people seem not to see it …

A man masturbated across from me and the woman sitting next to me on a bus one time. And he was moaning and saying things to us. And neither one of us stopped it or knew how to stop it. The rest of the passengers ignored it.

If you try to stand up, you risk being bullied or harassed further …

Was called a prude for objecting to Porn Fridays where female colleagues’ faces were Photoshopped on to porn pictures.

If you try to speak out you risk being belittled at best, disbelieved or blamed at worst …

When I was raped, people said I was asking for it, that I was a slut and I had led him on.

And yet, in spite of all this, people are standing up in their droves. According to the testimonies sent to Everyday Sexism, one group of teenage boys challenged sexism at their school by coming in wearing skirts to show solidarity with the girls. University students set up a new feminist society to protest sexual harassment on campus. An engineer who was sick of being asked to do other people’s photocopying broke the printer at work to avoid the problem. A woman sick of cold callers asking to speak to “the man of the house” started putting them on to her six-year-old son. An employee whose male colleague loudly accused her of being on her period when she disagreed with him replied: “If I had to bleed to find you annoying, I’d be anaemic.” A woman who was called an “opinionated lesbian cunt” responded: “Thank you. I’m proud of being opinionated, lesbian, and having a cunt.”

The Everyday Sexism Project has proved that we can change the shape of society if we stand together. Today, we are highlighting gender inequality on social media using the hashtag #EverydaySexism.

Every one of us has a moment when prejudice or inequality crosses our path, and we have a choice to make. Will you take a stand, or will you be the person who looks out of the window?