Women may be underrepresented in technology careers (something we hope changes soon!), but the importance of women in tech should not be underestimated.

From early (and often unheralded) innovations to CEOs of the biggest technology companies today, women in technology have been pivotal to technological advancement and the way we currently interact with the world. That’s important to recognize, particularly in a year when barriers are being broken for women in tech, even if there’s a long way to go. This spring Dartmouth graduated more female engineers than male for the first time. It’s a significant step forward. (Check out these top STEM colleges for women for good places to kick off your career.)

In recognition of that, here are five famous women in tech who, past and present, have laid the groundwork for the technologies we interact with on a daily basis.

1. Susan Wojcicki

The Harvard alum was the first marketing manager of Google back in the 90s. In fact, Google’s initial office was set up in Wojcicki’s garage. She rose within the company to become Google’s senior vice president of advertising and commerce. She developed AdSense, which is now Google’s second largest source of revenue. Wojcicki recommended the purchase of YouTube to Google’s board and handled its acquisition once the board approved the $1.65 billion purchase.

Now the CEO of YouTube, she’s been labeled “the most important Googler you’ve never heard of” and “the most powerful woman on the internet” and is frequently included in lists of the most powerful women in tech.

A mother of five, Wojcicki is a vocal advocate of paid maternity leave and the importance of work-life balance for professional women.