It’s the kind of holiday mail that might have been tossed aside, discarded like any other piece of junk mail: a special offer for a facial at a local spa.

Only the address on the letter no longer exists. And the woman the letter is addressed to died more than five years ago in the terrorist attack on the World Trade Center.

Hundreds of pieces of mail destined for the former trade center still arrive every day at a post office facing ground zero — the relics of the unfinished lives of Sept. 11 victims.

Telephone bills, insurance statements, wine club announcements, college alumni newsletters, even government checks populate the bundles of mail. Each bears the ZIP code once reserved exclusively for the twin towers: 10048.

‘’I guess sooner or later they’ll realize the towers aren’t back up,” said letter carrier Seprina Jones-Sims, who handles the trade center mail. ‘’I don’t know when.”

Some of the nation’s most recognizable companies and organizations, from retailers to research hospitals, are among those sending the mail. Much of it seems to result from businesses not updating their bulk mailing lists, said U.S. Postal Service spokeswoman Pat McGovern.

The postal service declined to identify the senders and recipients of the letters according to policy. Several companies formerly housed in the towers also declined comment.

The trade center mail meets varied fates once it arrives at the Church Street station.

A handful of companies pay for a service that forces the post office to hold the mail until a messenger picks it up. The rest of the mail travels various routes. Some will be returned to the sender, some will be forwarded to the company’s current address and some will be sent to a Brooklyn recycling firm to be destroyed.

That the Postal Service is even forwarding mail from a nonexistent address five years later is rare. ‘’Normally we’d only forward mail for a year, but we’re making an exception here,” McGovern said.

The trade center’s mail used to travel from the Church Street post office and up through the towers. It would start on the ground tucked in the letter carrier’s bag and continue up higher and higher — to the 68th floor, the 89th floor, the 104th floor.

The morning’s mail never made it through the flames and smoke on Sept. 11, 2001. It stayed put with the letter carriers, who silently observed the chaos that unfurled outside the post office.

Flying debris blew out most of its windows. After a three-year restoration, its doors officially reopened in August 2004.

Rafael Feliciano delivered mail to floors 78 through 100 of the south tower for three years. He watched the tower collapse on television from a bar several blocks away with a co-worker.

‘’He turned to me and said, ‘You just lost your route,”‘ Feliciano recalled. When the dust cleared, he spent weeks identifying office workers who came to pick up their mail, searching for familiar faces to see if they had survived.

Mail addressed to people who were killed was marked as deceased right away, he said. But it kept coming.

‘’It’s been five years later. How many people don’t know the towers are gone?” he said.

Jones, 39, took over the trade center mail after Feliciano — too shaken to enter tall buildings any longer — left his route to become a driver. She gets to work at 5 a.m. The mail is carefully divided among white plastic trays labeled by company name.

But the Church Street post office — built in 1935 and now on the National Register of Historic Places — is no longer the bustling hub it was when it stood just steps away from the city’s tallest buildings.

Between 2001 and 2002, the total weekly volume dropped from 1.2 million pieces to just 485,000. It has risen slightly in the years since.

The neighborhood is slowly awakening, attracting more and more residents and businesses after the exodus that occurred five years ago. The post office’s marble floors are newly polished and the building is brimming with employees. When they gaze out the long bay windows overlooking ground zero, they see nothing but blue sky.

‘’You start flashing back to that day,” Feliciano said. ‘’That’s why I got off the routes. It’s like a movie that plays over and over in your head.”