Credit: Michaela Winberg / Billy Penn

Calling it now: the Philly furnace party will become an annual event. Whether its surface is still a grassy lot or has been built up with new development, it’s entirely plausible to assume the corner of 27th and Girard will host an end-of-April get-together every year.

Will crowds at future shindigs remember how it all started? That’s far less clear.

The set of circumstances that led to the impromptu gathering — which drew several hundred dancing and beer-drinking people to an empty lot on Saturday afternoon — were an unusual confluence between hand-delivered preachings and internet meme culture.

Thanks to reporting from PhillyVoice, we can trace the origins of the furnace party to the semi-religious teachings of a 64-year-old man. His typed missive, spread by friends through a fast-gentrifying neighborhood, ended up being unique enough to catch the fancy of creative social media users and inspire the real life meetup.

When the mysterious letter first showed up on the scene, arriving on seemingly random doorsteps in Fairmount and Brewerytown in February, it was considered generally creepy.

Advised of its contents, which suggested that all the meat you’ve eaten since you were a kid would lead to a fiery demise unless your body was fused with metal, and ended with the polite-but-unsettling demand “Do attend,” police were somewhat alarmed. “Report it,” a PPD spokesperson told Billy Penn at the time. “Whatever it is.”

While a few people may have filed official reports, even more used the letter as fodder for photoshops and gifs and jokes. There were so many postings that an entirely new r/furnaceparty subreddit was created.

A connected fundraiser benefiting mental health services was also launched, because the wording in the note — for example: What is needed is a steel furnace where metal can be melted and the bodies of people and animals mixed with the metal to become steel unable to be hurt. Of course, you’ll be sedated first. — was just atypical enough to arouse concern about its author’s mental state.

No one was certain if the gathering described at the end of the memo would actually happen. The date set, April 27, seemed to hold little import, and the location was mostly unremarkable: an 8,000-square-foot lot at 27th and Girard. Once a bus depot and supermarket, according to Curbed, it has sat empty for the past two decades, despite some efforts at redevelopment.

But at the given date, place and time, plenty of intrepid Philadelphians showed up — including the letter-writer himself.

As described by reporter Brian Hickey, the author is 64-year-old Milton Jackson, a local resident who travels in a wheelchair and has experienced homelessness. Considered something of a spiritual teacher among his friends, he is known to them as ABBA, said people who accompanied him to the party. (The word “ABBA” topped the printed letter.) Jackson reportedly asked a disciple named Bessie Jones to type up the letter and distribute it.

While Jackson and friends are black, most of the attendees spinning tunes and dressing in steel furnace-inspired costumes on Saturday were white — but it didn’t seem to bother anyone.

Though they didn’t expect the note to go viral, Jackson’s friends and family said, they welcomed the big gathering, calling it and “beautiful” and “unbelievable.” Photos snapped after the event show the lot looking empty as ever, no trash or sign of disturbance.

Said Jones to 6ABC: “He wrote this letter to bring the community together in unification and purification.”

Only 12 months to go until Philly furnace party, year two.

Danya Henninger is director and editor of Billy Penn at WHYY, where she oversees the team, all editorial decisions, and all revenue generation — including the membership program. She is a former food...