Nobody is quite sure how long the four-and-a-half foot tall safe was nestled in the back half of a closet at the Old Pine Community Center in Society Hill.

It had been there so long — turned backward so its handle and dial didn’t show — that staffers at the center assumed it was just a large metal box or an outdated piece of mechanical equipment. And the wheels on the bottom of the heavy object were so rusted that nobody could move it, said executive director Mark Atwood.

“It was a part of the place,” he said.

But when the Old Pine Community Center, which has been the only tenant of the building at Fourth and Lombard Streets since it opened in 1977, was in need of more room this year, they called in a junk-removal company to help get rid of it in October.

“A large guy got it rocking, got it moving, and got it out,” Atwood said. “And that’s when we realized it was a safe.”

The front read “York Safe & Lock Co.” and it had a knob and a dial, but nobody knew the combination. Even the longest serving board member, who’s been with the center for more than 13 years, didn’t know the safe was there, Atwood said.

“We were going to just dump it but the curiosity was too much,” he said.

So center staffers sought estimates from locksmiths on opening the safe. Unfortunately, every quote was “just out of our price range,” Atwood said.

A staffer decided to post about the mystery safe on the neighborhood app, Nextdoor, asking if anyone had personal experience cracking open safes.

An Inquirer colleague who saw the post sent it my way and I reached out to Atwood and then created a Twitter thread about the mystery safe, seeking a volunteer to help open it on the center’s behalf.

Philly Twitter immediately became completely and utterly invested in the mystery. Responses included:

“I’m really going to need to know how this ends.”

“i am obsessed w this story.”

“This is the only thing I care about anymore.”

Of course, responses also included references to Jimmy Hoffa, Ant-Man, and Geraldo Rivera’s 1986 opening of a secret vault in Chicago that once belonged to Al Capone ― and turned out to be empty when he opened it on live TV (with 30 million watching).

A few people offered to try their hand (or volunteered their husband’s hand) to crack it open, but it was a suggestion from Philadelphia Fire Department Lt. Will Tung of Ladder 23 in Chinatown that Atwood found most intriguing. Tung suggested the center reach out to their closest firehouse with a ladder truck, which is Ladder 2 at Fourth and Arch Streets, to see if they could use their jaws of life to crack the safe.

On Friday afternoon, as the center was hosting about 30 young kids as part of an after-school program (many of whom tried cracking the safe themselves) Fire Department Capt. Thomas Johnson brought Ladder 2 and four firefighters to try and assist the center.

“Oh wow, I was hoping it was smaller,” Johnson said, when he saw the safe. “I don’t know how successful we’ll be. ... No pressure, nothing is on the line except for pride.”

It took all four firefighters to wheel the safe outside and away from the kids, who watched with their noses firmly pushed against the glass doors in excitement.

The firefighters first tried using a Halligan bar, a forcible entry tool used by firefighters that resembles a pick and axe, to knock the hinges off. They then brought out a carbide-tipped circular saw to finish cutting the hinges before finally using the jaws of life to pull the door off.

“We like looking for opportunities to train forcible entry,” Johnson said. “Unless there’s an active fire job we don’t have that opportunity to absolutely do it in a real situation and see what these tools can truly do.”

Behind the metal door, the safe was reinforced with concrete, which the firefighters chipped away to reveal another door that easily swung open.

And after weeks of speculation, the safe’s contents — not seen for years, or possibly decades — were finally revealed. Inside, Atwood and the firefighters discovered hundreds of … empty envelopes and three empty lock boxes, one of which had a note taped to it that read “Preview party admission $10.”

“This is about what I expected,” Atwood said. “I’m glad we didn’t pay someone to open it.”

Johnson said he and the firefighters were happy to help, even if an original copy of the Declaration of Independence wasn’t found inside.

“It’s not that we mind the envelopes, but it would have been cooler if they were from the 1700s,” he said.

The donation envelopes in the safe were so old they didn’t have the center’s website or email on them and the return information on the mailing envelopes was so outdated they can’t be used, Atwood said.

There was also a single yellow Post-it note inside with a name and phone number written on it (Syd Kobler, if you’re reading this the Old Pine Community Center would love to talk to you) and Atwood later found 30 cents in the safe, in the form of three dimes from the 1970s, 80s, and 90s.

The center will now try to find someone to haul away the safe. Atwood says he plans to save a few of the envelopes as mementos.

Back inside the center, 5-year-old Vincent didn’t try to temper his disappointment about the contents of the mystery safe.

“I don’t like envelopes,” he said. “I wish there was bananas and apples in it.”