We toured a massive Amazon warehouse. This is what it's like.

Amazon is under fresh scrutiny for the working conditions in its fulfillment centers, the massive warehouses across the country where packages are picked, sorted, and then sent to customers. On Wednesday, Sen. Bernie Sanders introduced the “Stop BEZOS Act,” a bill that appeared to directly target Amazon for underpaying those workers, and would fine large companies if their employees claim benefits like food stamps or medicaid.

Amazon isn’t taking this lying down, and is going on a charm offensive to push back against claims that its warehouse workers aren’t being treated fairly. Part of that includes offering tours of select warehouses across the country that are open to the public. So, we signed up for one at a 1.2 million square foot distribution center in Chester, Virginia.

Upon entering, you are greeted by a wall of eight foot high turnstiles, with the slogan “Work Hard. Have Fun. Make History” emblazoned above it. Like other Amazon warehouses, it’s located in an industrial park that houses other massive warehouses.

Before going past the turnstiles, we watched a short video that mentioned Amazon’s Emmy-nominated Prime original content, the use of robots in some warehouses, and stressed how much Amazon appreciated its warehouse associates. The video was fun and lighthearted as it showed all the steps necessary to get a toy giraffe to a customer.

Read: Bernie Sanders declares war on Amazon's CEO with BEZOS Act

Amazon didn’t let us bring cameras or take pictures on the tour, and the company’s penchant for secrecy was evident immediately. One of the tour participants asked the ambassador conducting our tour how many employees worked in the warehouse. He said he can't divulge that information.

Our tour group, run by Raul Gonzales, an operations manager at the fulfillment center, was led around a small area past huge conveyor belts and endless corridors of shelves. Standing in one of the rows of packages, it was hard to grasp just how big the warehouse was. Looking down the rows of aisles it was hard to tell where they stopped.

Inside the warehouse, there is a constant whirring noise produced by thousands of yellow bins moving on conveyor belts, across the warehouse and up the the second floor, where products are packaged.

Our guide extolled the virtues of working for Amazon while reading from pre-prepared notecards. Tour guests wore headphones that fed the audio from the guide’s voice, not unliked a guided tour through a museum. The warehouse had been prepared for tour guests, with designated parking spots, branded headphones and helpful signs to direct guests.

He made sure to point out that the warehouse has air conditioning. That’s probably because there have been multiple instances of Amazon warehouses getting so hot its employees fainted. He also talked at great length about all of the benefits available, from health care (which starts on your first day!) to tuition reimbursement.

Amy Bernard, who drove 75 miles from Virginia Beach with her husband to take the tour, said she was just curious how Amazon gets packages to her door. “I think it’s a good way to attract employees because they talked a lot about the benefits that Amazon has which are very good in my opinion,” she said. “But also just to show people that are wondering ‘how does this work?’ And just to go on the tour and see how it works gives the customer a better idea of how much work goes into getting your order correct and to your door on time.”

Asked if she had ever heard of claims by fulfillment center employees that they had been treated unfairly. “You wouldn’t know that, actually, from taking the tour,” Bernard said. “Because the people that we kind of encountered, smiled and waved.”

Her husband Elton also seemed impressed: “Just listening to him talk about the benefits and the career opportunities, those are impressive benefits, I think.”

We walked by one employee who was stationed at a standing desk grabbing packages off a conveyor belt to her left, putting them in boxes, taping them shut, and placing them back on the conveyor belt. “One of the benefits of working here is you get to play with giant bubble wrap,” our tour guide said.

While we weren't permitted to talk to employees, we did speak to a former worker at Chester, who had a different experience working there.

“We’re pretty much no more than a number or a statistic, that’s what I felt reduced to,” said Seth King, a Richmond resident who worked in the facility for two months after after leaving the Navy. “You know, seeing all the people that I started with quitting after the first week or two and how that was kind of their method. Just hire new people, exhaust them, push them til they can’t work anymore, then leave and have new people come in. And I was like part of that machine.”

Over 1,000 people have already taken the tour since 2014, according to signage at the facility, though. Amazon does not offer tours during “peak” season.

We saw “pickers,” employees who roamed the aisles, scanned packages and moved them to be sorted. Those pickers carry handheld scanners that tell them where in the warehouse they need to grab their next package. Once a picker scanned the package and placed it in the cart, the scanner populated with information about the next package to grab.

Our tour guide said that pickers can walk over 10 miles a day. “This gym pays you,” he said.

Once a product is packaged, it’s placed on another conveyor belt, where a robot applies the shipping label. If the robot determines the wrong item is placed in the package, it automatically gets taken off the line and the responsible employee gets “instant feedback” that they screwed up.

Toward the end of the 45-minute tour, our guide said he couldn’t show us the place where packages are loaded onto trucks, instead, the two children on the tour played a game where they competitively packed Amazon boxes into a fake semi-truck.

After that, we stood outside a classroom where fulfillment center employees who had worked there for more than a year were taking paralegal classes from a local community college. At the end of the tour, we were shown a gift shop where warehouse employees can buy Amazon swag, like t-shirts, socks and mugs. The tour guide said the gift shop was there so that employees could build team spirit.

Cover: An employee packs a box at the Amazon.com Inc. fulfillment center in Robbinsville, New Jersey, U.S., on Thursday, June 7, 2018. (Photo: Bess Adler/Bloomberg via Getty Images)