Why nearly 5,000 enthusiastic parents were running around Google's campus this week

On a hot Thursday morning in Mountain View, California, an enormous amphitheater usually crammed with rowdy concert-goers is packed with a very different kind of crowd.

Inside, thousands of Google employees squeeze in next to their parents, who are munching the remains of their free breakfasts, sipping from new logo-emblazoned water bottles, and listening to some of Google's top brass thank them for raising such a great group of people.

On stage, HR chief Laszlo Bock talks about the stunning amount of money that Google employees raised for victims of the earthquake in Nepal this past April and how a group actually travelled there to help relief efforts.

"This isn't Google making them do this," he says. "These are your kids, saying 'This stuff is important.'"

All three execs who spoke - Bock, Google maps head Jen Fitzpatrick, and operations VP Kristen Gil - drove home a similar narrative: Google's vast technological innovations are only possible thanks to the caliber of its employees - "your sons and daughters!" So it's no surprise that the session wrapped up with some damp eyes.

The heartfelt speeches were just Part One of a full day's worth of activities, including workshops, classes, and free food galore. The day culminated in a special "TGIF" question-and-answer session with cofounders Larry Page and Sergey Brin, where parents were encouraged to ask the founders whatever questions they wanted.

It was the company's third official Take Your Parents to Work Day at its headquarters, and relatives had flocked to Silicon Valley from all over the country, and the world, to celebrate. In total, about 3,000 Googlers and 4,700 of their parents took part, with families making the trek from as far away as Qatar, New Zealand, and Serbia.

"We do it to thank parents, because for many of us, they're part of what got us to a place like Google," Annie Robinson, a manager on the HR team that set up the event, told Business Insider. "The other big thing is that we want to peel back the curtain. Because behind the free food, we want to show them what their sons and daughters actually do here."

Parents just don't understand

Although parents can proudly spout info about Google's "moonshot" projects and legendary perks, many admit that they don't fully understand their progeny's place in it all. They're not alone: A LinkedIn survey from a couple years ago showed that more than 2/3 of parents are not completely familiar with what their kids actually do.

"We don't really understand yet," Mrs. Woodworth, on campus to visit her daughter Amber, who works on Google Fiber, confessed with a laugh. "But we hope to find out today!"

The family planned to watch the TGIF together with Amber's teammates and their respective parents later that day.

They'd likely even get to meet her manager.

Robinson says that Baby Boomer parents often feel pleasantly surprised by Google's open, non-hierarchical structure.

"A lot of parents have the perception of a 'boss' as someone in a corner office who their children might never talk to, versus as a person who stands next to them at a standing desk," Robinson says. (When her parents came for the last TYPTWD, her manager spent a moment complimenting her contribution to the team and she says they glowed the rest of the day.)

Besides putting faces to the names they've heard about while exploring the curated oddities of the Googleplex, parents could attend workshops for things like learning how to upload their own videos to YouTube or book their next vacation with Google Flights.

They wandered between discussions like "Unconscious Bias at Work," where they learned about the company's efforts to increase diversity, and meditation class similar to Google's insanely popular "Search Inside Yourself" class (the session we attended quickly filled to capacity). Google even had an autonomous car available for parents to gawk at, though unfortunately not take for a spin.

Everywhere you turned, employees and their parents - many of whom rocked Google t-shirts, hats, or even propellered-beanies - were posing for pictures in front of Android statues or next to the company's signature rainbow bikes.

One couple said that their friends back home urged them to take tons of photos and report back if it really looks like it does in the movie "The Internship."

Parental-drive retention

Robinson says the company does all it can to make the day special and memorable for the parents.

But it has big benefits for the company too. One employee told us that getting to meet everyone's parents reminded her to be more empathetic to her peers. Plus, bragging to their parents about how amazing their job is might make them more likely to stay there.

Although Robinson said that she didn't have any research into how it works for retention, that's likely part of the equation.

"Companies are now realizing that it's really hard to maintain loyalty and retention, and one of the things that they found is that millennials listen to their parents," Lindsey Pollak, who has written several best-selling books about millennials in the workplace, told The Huffington Post. "I used to joke that one day we would have Take Your Parents To Work Day and people used to laugh. It was inevitable."

If the day comes when a Googler thinks they might want to leave, having had their parents see the lush campus and listen to multiple speeches about why it's the best company ever might make those "golden handcuffs" a little tighter.

But, until then, the biggest takeaways from the day will probably be a bunch of cute photos and feelings of assurance parents that their kids are working somewhere that cares deeply about both their work, but also their overall well-being, too.

"This is just such a joyful place," one mother summed up happily. "Despite all the chaos," her husband adds with a laugh.