In these shows, Drysdale lays out a curated selection of the antique stereoscopic slides he's collected for decades -- all taken between the 1940s and 1960s. He also hands every guest a rare handheld stereo viewer to display the slides, and encourages his audience to take a look.

"It feels like magic," said Cassidy Routh, a designer and animator who has been to the show four times.

"It feels like you're walking into the past," she said. "Especially in this society that's obsessed with virtual reality. ... We did it in the '40s perfectly and now we're doing it again."

Talk of slides and handheld viewers often brings to mind the View-Masters that many people recall from childhood, said Avery Trufelman, a superfan of the events and the radio producer behind the hit fashion podcast "Articles of Interest." She said she has to work hard to convince the people she brings to Drysdale's shows that this is something completely different.

"It's like this little tiny movie theater right in your eyes," Trufelman said. "So you have these luminescent, three-dimensional images. You're so close to the past."

Drysdale said getting people to come to his show for the first time is difficult, but that those who do tend to return throughout the years.

"The majority of people who come don't have any idea what they're in for," Drysdale said. "But they've usually gotten some kind of glowing recommendation that they couldn't ignore."

In the 1950s, America experienced a short-lived craze for 3-D stereoscopic images, and about a million households had special cameras for it, Drysdale said.

He discovered the medium in the early 1990s, when his then-girlfriend asked him to look at some old camera equipment in her grandmother's house.

"I put one of the slides into the viewer and it was an incredible 3-D photo of my wife's great-great-grandmother, a recent immigrant straight from the shtetl, being dragged along on a trip to Parrot Jungle in Florida, with parrots all over her," Drysdale said.

He found the image bizarre, breathtaking in 3-D, and "crazily, aspirationally American."

The very next day, at a flea market, Drysdale found a few more of the special slides. He's been collecting them ever since and now has more than 30,000, though he brings only a curated selection to his shows -- slides taken by regular Americans, often at everyday events, that somehow capture the past in a more than lifelike fashion.