No matter how many shiny, starchitect-helmed tech campuses you cram into it, the Silicon Valley’s most remarkable architectural landmark will forever be a rambling Victorian mansion continuously built over a 38-year span by a very rich, very paranoid widow.

Functioning as a sort of Hearst Castle of the Uncanny, San Jose’s Winchester Mystery House stands as a National Register of Historic Places-listed testament to the fractured psyche of firearms heiress Sarah Pardee Winchester. Spanning 24,000 square feet, the labyrinthine residence is architecturally stunning despite its not-so-subtle eccentricities. Features such as forced-air heating and push-bottom gas lighting were considered state-of-the-art during the time of its nonstop construction from 1884 to Winchester's death in 1922.

That being said, the home is really quite something to behold: 2,000 doors, 10,000 windows, 47 fireplaces, 47 staircases, 52 skylights, six kitchens, three elevators, two basements and 13 bathrooms. Naturally, the 13th bathroom has 13 windows and 13 stairs leading up to it. There’s only one lonely shower in the entire joint, which is actually rather surprising given that you'd assume Winchester didn’t have the time for leisurely baths. After all, she spent nearly half her life overseeing a team of 13 (!) dutiful carpenters and, as legend has it, fleeing from the antagonistic spirits of those killed by rifles manufactured by the company founded by her late's husband's father.

Winchester Mystery House, San Jose, California, exterior Currently topping out at four stories, sections of millionaire occult-dabbler Sarah Winchester's disorienting funhouse of a mansion reached seven-stories-high prior to an earthquake that rocked the Bay Area in 1906. (Photo: San Jose Library/flickr)

Until recently, it was also believed that this habitable maze complete with trap doors, false passageways and upside down columns— you’ve got to confuse those malevolent spirits somehow, right? — had a total of 160 rooms spread out across its six-acre footprint.

Well, they’ve just found another.

As reported by the San Francisco Chronicle, preservationists at the private home-turned-tourist attraction have unearthed a previously unknown and unexplored attic room that Winchester allegedly took refuge in during the historic earthquake that rattled the Bay Area in 1906. Winchester, rumored to who have believed that the same pesky poltergeists populated her home were also responsible for the tremor, subsequently boarded up the room and never entered it again. This may seem like an exceedingly odd action for a homeowner to take but keep in mind that this was a homeowner who had a penchant for both exquisite Tiffany stained glass and doors that open onto walls. Sealing up entire sections of the mansion were as routine for Winchester's staff as waxing the parquet floors.

You can see more of the mansion, which started out as modest eight-room farm house set against apricot orchards, in this video:

To play skeptic for a moment, it is peculiar that it took this long for the hidden attic room to be discovered considering the tireless preservation work that has been carried out at the mansion, open to the public since 1932, for decades now. Impossible, no — but implausible, sure, and more than just a bit considering that the Winchester Mystery House is one of San Jose’s top tourist attraction and Halloween is just around the corner.

What's more, some sources claim that Winchester sought shelter during the earthquake in a different room altogether.

As noted by the Smithsonian earlier this year, delayed discoveries of hidden rooms within the enigmatic mansion aren't totally unprecedented. In 1975, restoration workers unearthed a room containing nothing more than a couple of chairs and a turn-of-the-century speaker. Apparently, Winchester had forgotten about it during the frenzy of building that went on 24/7 for 38 years straight.

Whatever the case, the 161st room is currently not open for public tours although frequent visitors with "Skeleton Key" memberships will be able to access the attic area and take a peek at the freshly disinterred chamber. As for the items reportedly discovered in the hidden room — a dress form, pump organ, artwork, sewing machines, Victorian couch and, from the looks of it, at least one creepy doll — they've been relocated to a more accessible area of the mansion’s grounds where they’ll be on display as part of a new attraction dubbed Sarah’s Attic Shooting Gallery.

Sarah Winchester portraitConnecticut-born Sarah Winchester herself is the subject of an upcoming supernatural thriller that will star Helen Mirren as the planchette-toting rifle heiress who, unfortunately for historians, never kept a journal and employed notoriously tight-lipped staff. The biopic will reportedly be shot on location at the mansion, which is currently offering seasonal Halloween Candlelight Tours and remains an inexplicably popular spot for kids' birthday parties.

It should be pointed out that many believe the legend of kooky old Sarah Winchester to be just that — a tourist dollar-generating legend that's been masterfully honed over the decades. Some argue that actual paranormal activity had little to no role in the decidedly bonkers design of the home and that Winchester, noted just as much for her philanthropy as her obsessiveness, was simply a brilliant yet misunderstood millionaire spinster that perhaps suffered from some form of mental illness.

In her myth-dispelling 2012 book "Captive of the Labyrinth," writer Mary Jo Ignoffo theorizes that some of the mansion's more perplexing architectural features such as a staircase leading up to a ceiling and a skylight installed into a floor are the result of uncompleted repairs undertaken following the 1906 earthquake.

Those in the pro-ghost camp, however, are convinced that the nonstop home-building/renovating/redecorating (estimated total price tag: $5.5 million) wasn't just a way for Winchester to confuse and evade the irate spirits of gun violence victims. As the Winchester Mystery House website elaborates, Winchester also strived to accommodate non-vengeful supernatural entities and held nightly séances to commune with them. In a sense, these spirits served as the unofficial architects of the master plan-less home.

If anything, Winchester’s need to appease "good" spirits does help to explain the staggering size of the property. After all, during her lifetime, Winchester rifles — the so-called "Gun That Won the West" — were responsible for the deaths of legions of people. And so, the eccentric and extraordinarily wealthy woman whose married name appeared on these firearms made it her life mission to provide displaced benevolent ghosts with a place to call home sweet home.

And what a home it is.

Sarah Winchester portrait: Public domain

Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.