Some of us have trouble remembering what we were doing a week ago, or even last night. But Tom Warner, of Great Barrington, Mass., can say exactly where he was on the evening of September 1, 1969.

"I was laying right where we’re standing right here," Warner said recently, standing in a yard with a stunning view of the Berkshires. "I was laying on the ground, like this, and there was a beam on me."

As Warner tells it, that beam was emanating from an object that resembled nothing he’d ever seen.

"Twenty feet or more in height, probably about 30 to 40 feet around, and it had — as I’m looking now, I can see it — it had lights," Warner recalled. "The lights were colors I’d never seen in my life."

To skeptics, this tale of a close encounter half a century ago might sound implausible. But Warner isn’t the only one convinced he witnessed something remarkable that night.

"Back in 1969, we had listeners call the radio station that evening," says David Isy, the general manager of Great Barrington-based WSBS. "They didn’t know it was a UFO at the time. They just called the station and said, 'Something bizarre is happening.'

"We talked about it on the air just last week, and one of our listeners, Jane Brown, who’s now 84, she called in to the radio station and told us she was one of the first people to report it."

These distant memories are back in the news thanks to a monument near a covered bridge in the neighboring town of Sheffield, where a man named Thom Reed says he and his family had their own close encounter that evening.

"This light, it rose up maybe two, three stories —and it went, actually, further away from our vehicle, over what’s now a large cornfield," Reed told WGBH.

The monument in question didn't arrive until much later, in 2015, after the Great Barrington Historical Society took the unusual step of calling Reed’s account “historically significant and true." But now, its future is in jeopardy.

The town of Sheffield said recently the monument might be on public property, which could lead to its removal. The citation from Governor Charlie Baker praising Reed’s family that adorns the monument's face has lost some luster, too: recently, a spokesperson for Baker told the Boston Globe it was issued in error.

The Great Barrington Historical Society seems to have some buyer’s remorse as well.

"I think the historical society regrets that our words, or our decision, has been taken out of context," said Robert Krol, the society's executive director.

Not that the events of that night weren’t significant, Krol hastens to add. But Krol — who wasn’t there when the historical society first weighed in — believes that, in retrospect, it was a mistake to focus so much attention on one man, instead of everyone else who witnessed something inexplicable that night.

"Children coming into school, talking about the event," Krol said. "An old student of mine! One is a local shop owner whose father was the...police chief in town. So these are reliable people. These are not self-promoters."

That seems like a jibe at Thom Reed, who’s detailed his story in multiple media venues, and gone further than many of his former neighbors. In 2015, for example, Reed told UFO Hub he'd seen a creature resembling "an ant, with some human features. It had a head that looked almost like a football shape." (He's also reported additional encounters with UFOs.)

In comparison, Tom Warner has kept a relatively low profile. But like Reed, he’s convinced that the Sheffield monument commemorates something significant — and that forgetting that evening would be a mistake.

"When you see something, it’s like — I see you. I see that rock. I see that building." Warner said. "I saw that UFO."