Jan. 20, 1969: On the same night that President Richard Nixon celebrated his first inauguration, a relatively unknown band named Led Zeppelin walked onstage in a modest gymnasium in Wheaton, Maryland, and played a set for a crowd of 50 or so local teenagers.

The concert was part of the band’s first American tour, the one that’d turn them into one of the most famous rock bands in history. They’d go on to be inducted into the Rock & Roll Hall of Fame and become the fifth best-selling band of all time in the U.S.

Er, wait. Come to think of it, maybe that concert didn’t happen at all.

What the…?

There are no pictures, ticket stubs, posters or other proof that the Wheaton concert happened — except for a couple people’s memories.

There’s Marc Elrich, the Montgomery County Executive, who says he remembers seeing the band play that winter night at the Wheaton Youth Center. It was a popular venue at the time for up-and-coming acts.

An engineer named Anne Marie Pemberton says she was there, too. She can visualize in her mind’s eye where each of the four band members stood in the room. Liquor salesman Tom McAleer told the Washington Post in 2009 that he wore white Chuck Taylor high tops to the show.

“It’s just like this folklore,” said local filmmaker Jeff Krulik, “something that’s been passed down from generation to generation.”

Krulik became so fascinated by the supposed concert that he made a documentary about it in 2013. The movie, “Led Zeppelin Played Here,” captures people’s recollections of the concert, the venue, and the growth of the concert industry in the D.C. region. The AFI Silver Theatre in Silver Spring will screen the film on Jan. 20 to mark the 50th anniversary of the concert.

So did he figure it out?

In short, no.

Krulik personally believes the concert happened, but he doesn’t have any hard evidence.

“Most of the stories make sense,” he said of the testimonies he collected. A handful of people told him the band seemed frustrated with the acoustics and the size of the crowd. If they were worn out and annoyed, it’d make sense — they’d played in Detroit the night before, 600 miles away by car.

The lack of material proof of the concert makes some amount of sense, too. The concert industrial complex as it’s known today was still in its nascent stages. Radio DJs and promoters got the word out about shows on their radio shows and by word-of-mouth. Krulik called it “a wild west atmosphere.”

“This was considered a phantom concert,” he said of the Zeppelin show. “But in this day and age, people want concrete proof.”

Krulik did get a hold of Barry Richards, a popular DJ and promoter at the time who booked numerous acts for the Wheaton Youth Center. Richard swore the concert happened — he even remembered getting chewed out by Led Zeppelin’s manager, Peter Grant, for how small the crowd was.

A love of place

Funny thing is, Krulik isn’t much of a Zeppelin fan himself. The Wheaton Youth Center is what really drew him in.

“The building moved me to want to make something to document the time period,” said Krulik, a Bowie, Md., native. He came to view the center, which opened in 1963, as a character in its own right.

The county decided to tear the building down a few years ago. Krulik fought to save it, but with no luck. A combination library and recreation center is getting built on the same site.

“It was a diverse-looking part of the landscape,” he said as he looked out onto the plot of land where the building once stood. Turns out, trying to convince local leaders that a gymnasium from the 1960s is historically and architecturally significant isn’t an easy fight to win — even if Led Zeppelin played there.

Or, you know, maybe they didn’t.

This story originally appeared at WAMU.