Valar more-spoilers. A girl must science. 

Game of Thrones creators David Benioff and D. B. Weiss finally gave us a peek into the lives of the Faceless Men on last week’s episode “Unbowed, Unbent, Unbroken,” and it didn’t dissapoint. The religious cohort of skin-changers was first introduced to viewers by the badassery of assassin Jaqen H’ghar, who helped Arya Stark escape from Harrenhal in Season two. Now, years (and too many deaths to count) later, Stark has traveled to the House of Black and White – the mysterious home of the Faceless Men in the city of Braavos – where she hopes to become one herself.

After weeks of washing bodies and sweeping floors, Stark was led by H’ghar to the Hall of Faces – a cavernous chamber filled with ornate, stone carvings and thousands of severed heads. Yes.

“I don’t know if it’s the creepiest place we’ve seen in the series, but it’s definitely one of the creepy ones,” says actor Tom Wlaschiha, who plays H’ghar. “It was really quite amazing what they built [at the studio]. When I first read the episodes, I imagined that there would be a lot of CGI and green screen in those scenes, and there was – but the sets had actually been built a lot more than I imagined. In the Hall of Faces, there were hundreds and hundreds of masks on the walls. It was really quite eerie.”

Unlike the decrepit-skin masks we expected, the faces in the episode appeared to be preserved in life-like condition. Creeptastic achievement unlocked…but could this treasure trove of death exist in our world? Actually, yes. Because, Science.

Museum collections around the world hold millions of wet specimens, most of which have been “fixed” with formalin (a mixture of water and formaldehyde) and placed in jars of alcohol for long-time storage. The process has been used for centuries, but as you probably noticed, it doesn’t quite fit the bill for the Hall of Faces specimens, which are not stored in jars at all. “That’s because these specimens would have been embalmed,” explains osteo-preparation and preservation specialist Darien Baysinger of Custom Cranium. “Alcohol storage protects DNA – which is great for scientists, but unnecesary for the Faceless Men.”

Baysinger explains that for H’ghar and his crew, embalming would have been prefereable to liquid-storage for a number of reasons. “For starters, no glass jars,” she says. “Which are a cost, especially at that time, when they would’ve been handmade (and there hasn’t been any indication of widespread use of glass in The Realm anyhow).” Then there’s the big boom factor: while alcohol is great for storing specimens, its vapors are also very good at igniting. Museums combat this by keeping their collection rooms below the flash point of ethanol, approximately 16.60 degrees Celcius (61.88 °F). Because the Hall of Faces is underground, it’s possible that the room would’ve stayed cold enough, but unless checking the HBW thermostat explains H’ghar’s constant disappearances, we’re ruling the Futurama method out.

When it comes to preserving dead bodies, it’s is all about proteins. Proteins are the building blocks of tissues, and must be stabilized (or “fixed”) if those tissues are to withstand the test of time. In the same way formaldehyde works now, the extracts and chemicals used in early embalming relied on molecules that were small enough to quickly penetrate the body’s cells, complete the fixing process, and stop decomposition. After being thouroughly washed, the soon-to-be-floating heads would’ve been drained of bodily fluids, and filled with the preservative mixture.

“It’s similar to what the ancient Egyptians did,” says Baysinger. “But mummification would have given the faces a gaunt appearance. To keep the skin supple, the chemicals would need to stay inside the tissues.” To achieve this, the Faceless Men would have sealed the, nose, ears, mouth, and neck – likely with wax and hidden stitches.

The skin would be treated with a light tanning mixture containing potassium nitrate, which has long been used by keepers of the dead to help skin retain its texture and hue. “If they were going to be very detailed about it, they may have placed simple inserts to keep the shape of the features, like clay eye covers under the eyelids, maybe wax inside the nostrils, and perhaps even subcutaneous cheek implants,” she adds.

All said and done, it would have taken about a week to embalm a face, which could then be put on a shelf to cure. My first thought, of course, was “what did it smell like in there?” According to Baysinger, embalming chemicals give off a sweet smell, and it wouldn’t have been horrible. “There would have been a slight scent of decay, but that would have wafted up towards the higher-placed heads.” Safely resting in the dark, dry hall, the faces would have lasted between 20 and 30 years – leaving plenty of time for new sacrifices to come ’round for a little sip from death’s fountain.

Of course, there might be something a bit more mystical going on in the GoT universe, but it’s totally plausible that they would have kept those cubbies full, so long as they moved the less viable heads out as new ones came in.

Images: HBO