Something strange was sighted in the skies over a Melbourne school on April 6, 1966.

Described by the students, teachers and others who saw it as a large, circular, silvery object – or objects – it appeared above the Westall High School oval before descending towards a patch of adjacent bushland known as The Grange.

 “I just shrieked, ‘There’s a flying saucer’. And that’s when the commotion started,” recalls former student Tania Vassie in a new episode of ABC TV’s Australian Story.

Vassie is one of several witnesses interviewed for the program, which will be broadcast on the 60th anniversary of what is said to be the largest mass UFO sighting in Australian history.

The ABC says The Westall UFO Mystery will include fresh first-hand accounts and investigate several theories about what might have been behind the incident in Melbourne’s south-east, during which three mysterious objects were reportedly seen in the sky by up to 200 eyewitnesses.

“What frustrates me and I think the other witnesses is the attempt of having it buried,” says Vassie, who was 13 at the time.

“Can we just find out what it is, please? That’s all we want.”

Retired school principal Ken Stallard, who was 15 at the time, tells Australian Story the flying object he saw was “large, easily visible, circular, silver and clearly under some form of control”.

“So many of us saw it,” Stallard said in a previous interview with the Greater Dandenong Leader in 2005.

“It never occurred to us that it didn’t happen or was an optical illusion. If it was, it was a pretty good optical illusion. It was 1966 … the space race was at its best. It was a mysterious time.”

Around a week after the incident, the Dandenong Journal published an article with the headline “FLYING SAUCER MYSTERY: SCHOOL SILENT”, in which it was claimed that investigations had been hampered by the fact school authorities wouldn’t allow interviews with students and staff members.

A 1996 page from Westall High School journal The Clayton Calendar.

On April 21, it ran another story saying the mystery had deepened, with the UFO “almost certainly” observed by the pilots of several light aircraft seen to be flying close to the object and chasing it.

The newspaper added that a detailed description given by a science teacher had “discounted theories that the object was a weather balloon, an aircraft or a flock of birds”.

Some of the eyewitness descriptions are recounted in a 2024 blog article by Terri Berends on the State Library of Victoria website.

“Reports from eyewitnesses claim that just before morning recess a series of ‘dazzling silvery object(s)’ appeared over high school oval, moving toward The Grange,” Berends wrote, quoting from articles published by the Dandenong Journal and the Westall High School’s journal The Clayton Calendar.

“One of the objects was larger than the others, with witnesses describing it as ’round with a hump on top and round things underneath’ or as an object that was ‘silver grey’ and seemed to ‘thicken’ sometimes.”

As well as being widely reported at the time, the mystery has continued to fascinate people in the six decades since, sparking numerous articles, documentaries and videos.

Australian writer Tim the Yowie Man reckons there is no doubt it can be classified as one of the “great Australian mysteries”.

“This was a big event, because so many people saw it,” he said in an Australian Geographic Instagram post last year.

“Most people believe that it was some sort of military experiment, due to its top secret nature… to this day, no one has been able to solve or reveal exactly what the Westall UFO was.”

He noted that one flying object was said to have landed in a paddock and left a circle in the grass, where people later reported seeing military personnel “with Geiger counters and the like”.

Just last year, Australian UFO researcher Grant Lavac, who produced a YouTube documentary about the sighting in 2023, lodged a petition to parliament requesting an independent inquiry into the incident.

“Despite the scale of this event, no official inquiry has ever been conducted, leaving a significant moment in Australian history shrouded in mystery and secrecy,” the petition said.

The petition also repeated allegations of a government cover-up, “including the rapid response of military personnel, confiscation of evidence, witness intimidation and non-disclosure of a comprehensive report compiled by the then Department of Supply”.

Australian Story will explore the theories that the objects may have been classified military technology or high-flying balloons testing radioactive fallout.

Former Westall teacher Shane Ryan, who began looking into the incident in 2005, tells the program that some of the about 140 witnesses he has interviewed over the years recall the arrival of men in uniform at the school.

“It’s amazing to me that there’s so much commonality across the witness testimonies,” he says. “People clearly remember there being a military presence.”

Richard Saunders, from Australian Skeptics Inc, is – unsurprisingly – more sceptical.

“Of course, something must have happened. It’s just trying to find the most reasonable explanation.

“People would rather jump to a conclusion which is quite far-fetched and be satisfied than simply say, we just don’t know.”

Today, the Grange Reserve where the “flying saucers” were seen is home to a UFO-themed park.

“The playground’s UFO doesn’t fly, but contains rope ladders, and steering wheel and controls, and two slides to escape the cockpit in a hurry,” says the City of Kingston website.

Australian Story will air The Westall UFO Mystery at 8pm on April 6. It will also be available on ABC iView