An Emily Carr painting.

"One of my old neighbors had an Emily Carr painting. He had an art book on a pedestal in front of it that talked about the painting and had the location as 'Unknown.' He had written 'Ha-ha!' next to it in the margin."

- fistymitts

"In my opinion, it was definitely stolen. Maybe not by him but...there's no reason not to claim it as an asset at least to insure it, considering its worth millions of dollars, unless claiming it would become a problem for you."

- PlayerH8rsBallz

"He's definitely a legitimate art collector. He probably got it in a private sale where the [provenance] was exclusively from private sales."

- fistymitts

A silent short film.

"My answer is something the public will likely never see, not because it's in private hands, but because all traces of it have likely been lost:"

"On May 16th, 1912, the American silent short film Saved from the Titanic premiered in theaters starring actress Dorothy Gibson. The film was unique in that, not only was it completed literally a month after the tragedy, but Gibson was one of the survivors of the disaster, even wearing the same nightgown she wore on April 15th in the film."

"Despite some papers like the New York Dramatic Mirror criticizing the film as "revolting," due to the recent nature of the disaster, many more praised it for the same reasons. And, indeed, its use of stock footage of Captain Smith aboard the near-identical Olympic, icebergs in the North Atlantic, and of the Olympic herself as a stand-in, was able to increase the film's authenticity in ways no other film could."

"Sadly, this would be Gibson's last film, as she suffered an existential crisis during production, and all known copies of the film itself were destroyed in a studio fire in March 1914. All of them."

"Except, perhaps one."

"You see, one of the more notable fatalities in the Titanic disaster was Major Archibald Butt. While basically everything he was said to have done during the sinking was a case of media sensationalism, what could not be fabricated was his friendship and role as military advisor to William Howard Taft, better known as the President of the United States. Taft, to say the least, didn't take the news well, breaking down into tears during Butt's second funeral ceremony on May 5th. He received a personal copy of the film, and as such, it is possible that this copy still exists today, tucked away and forgotten…."

- Shipping_Architect

A lost room.

"The Amber Room."

"It ended up somewhere."

- DNAeros

"As much as I would live to see it I don't believe it exists anymore. There may be pieces of it in collections but the majority of it must have been broken apart and sold to be made into other trinkets."

- Ascholay

"The consensus among most reputable historians and journalists is that the Amber Room was destroyed during the firebombing of the building where it was held, though individual pieces might have been looted as people fled the palace and sold later, fueling rumors that the room itself had survived."

"Notably, none of these rumors have led to a plausible theory of how the room might have been moved and stored. When you take into account that:"

• "It's very common for portable items of value to be looted during the destruction of culturally significant sites without the site itself surviving;"
• "The Amber Room would have been incredibly difficult to move, hide, and store, particularly in secret;"
• "And that all leads regarding its whereabouts so far have been proven false"

"... Then there is no actual evidence that it survived, besides wishful thinking and the fact that it makes a good story."

"Also worth noting, the destruction of the Amber Room was seen as extremely bad PR for everyone involved, so there is great motivation for powerful states and figures to produce the room, if it exists, yet they have been unable to do so."

- lemontreelemur

"The thing is it's probably still around in the place where it was made, Prussia. In fact the Amber Room has a high chance of still being in the remains of Konigsberg Castle. The area of Konigsberg is now called Kaliningrad Oblast and is a Russian territory. The soviets blew up the remains of the castle in the 50s and 60s after it sustained heavy bombardment in ww2, however, the castle was so big that the basement/cellars/foundations all still exist. As far as I am aware, Konigsberg Castle was the last place the Amber Room was seen and it may by in the cellars/tunnels underneath the remains of the Castle."

"There is currently funding for a project to dig up the remains of the Castle and go into the tunnels underneath the foundations of the two main fortified towers that have been blown mostly to smithereens."

- GoldPrussianEagle

Art on rotation.

"I know there's a ton of stuff that the Nazis stole that still hasn't been recovered. Plenty of it HAS to just be sitting in somebody's living room, with the owner possibly being unaware of its origins, or maybe at least suspicious of its origins but they don't want to contact anybody about it."

"Museums also have a ton of stuff that they keep behind the scenes for various reasons - I think usually sensitivity to light and needing better temperature and air control are the main ones. Some of that stuff has really good replicas that are actually what's on display in museums, but I think a lot of the stuff doesn't so is just in some drawer in the back room somewhere where only specific employees and documentary filmmakers can see it."

- OneGoodRib

"Apparently, because of how they 'rotate' exhibits & collections, museums typically have far more things in storage than on display."

- JustHereForCookies17

"They also share with other museums, got to keep the attractions fresh."

- Psyco_diver

"They have even more than that I'd say. Stuff admitted in the museum often have additional items on the side that get mixed up and unlabeled; some dresses have sample extras on the side for reparation or replication purposes for the original owner."

- Gemela12

"My mom works at a small museum and she says that they normally have about a third of their collection on display. Also, many pieces have restrictions about how long and how often they can be displayed, especially older paintings and delicate pieces like tapestries. For these reasons, museums often borrow pieces from private collectors to 'fill out' exhibits"

- I-grow-flowers

"Hell even in the university I work in, we have a small museum, with literally just a few select biological pieces. But we have a locked room with thousands of specimens that would fill the room 3 times over."

- Goetre

"Same, the University I'm at (I don't work there, I'm a student) has an enormous collection of Greek and Roman artefacts; there are like six pieces on display in the hallway, but on the top three floors the fifth-year and Master's students love getting sh*t out if you ask them. Three. Floors."

- Gr0und0ne

"My gf's family has an old bed frame they dismantled and buried when the Nazis starting taking sh*t, they eventually dug it up and reassembled it and now it's in like a guest room but it was all metal very well crafted."

- bugzillian

The Most Unexplained Events In History | George Takei’s Oh Myyy

"Lost" media footage.

"Lost Media footage. I know some collectors stumbled upon gems but won't release it, because the like the power of feeling like a god."

- Prince_Jaehaerys

"For obvious reasons there are quite a few recordings of fatal racing accidents that are locked away forever either by the families or the racing team owners/manufacturers. I'm ok with these staying that way."

- TRex_N_Truex

"I know this was being discussed after Steve Irwin died, since his death was caught on tape. I'd heard that the Australian government ordered the footage destroyed once the inquiry into his death was completed. Given how much of an icon Steve Irwin was, especially in Australia, I'm certain that all of the footage was destroyed, especially since all the people who witnessed it were his friends. I'm perfectly fine with that footage being destroyed."

- PAKMan1988

"For a looooong time only 1 person was known to have footage of the entire first super bowl and flat-out refused to give it to NBC. To the point that NBC had to cobble together a tape from various other sources for the 50th anniversary."

- I-grow-flowers

Someone commented an article about a kickstarter to get the footage.

"I know DJ Mike Nice has the footage of the 'unrecognized' NWA Title change between Ric Flair and Jack Veneno in the Dominican Republic… probably not technically LOST but super rare."

- shawntitanNJ

Medieval manuscripts.

"Well maybe not in private collections, but as someone majoring in European Medieval History it kinda pains my hard that there are some beautifully illuminated manuscripts, that almost no one but the conservators will ever be able to lay their eyes upon. The Book of Hours of Jean de Berry bursting with life and colour, the Utrecht Psalter, the oldest & most valuable manuscript located within my country, dating back to the 830's and decorated with incredibly precise and lively pen drawings and so much more. You can check digital versions online, but to hold such a piece of history and art in your hands is another experience entirely."

- Wampderdam98

"It amazed me when I visited the bayeux tapestry. The colour and condition of something coming up on 1000 years old. Some of the detail they put into those old manuscripts and tapestries are unbelievable."

- michaelscottdundmiff

"Dude I cried when I saw this old a** painting from el Greco. Like how can something soooo old survive. How am I seeing this painting. Same when I saw Van Gogh paintings."

- Jen_Mari_Apa

"It's pretty important that people can't just come and handle it though. The only reason it's survived this long is because it has been handled extremely carefully. It probably won't be long before a technology comes along that makes current high definition digital images look outdated, just as they make black and white photographs look outdated."

- mordenty

Stradivarius violins.

"Few Stradivarius violins."

- Adonis_X

"I worked for a year for a big insurance company and I was helping an underwriter finalize some documents for a plan and it was this guy who had three of those violins."

"It's crazy to have even one, but three?!"

- UCMCoyote

"Stradivarius cellos are even rarer than the violins. Knew a cellist who was loaned one for concerts. Bought 2 plane tickets whenever he traveled with it, one for the cello."

- Cherimoose

International drama.

"I work at a very fine auction house. I know where most of the European, Russian and ancient China art goes. And who bought what since WWII."

"I have no idea how much trouble I would get into, but I know of sales that would cause some international drama."

- Antieque

"See, we need a Wikileaks situation for this kind of stuff."

- IngsocInnerParty

"A lot of very wealthy collectors have little trust in their relatives, so they grow a concern of what happens to their collections when they die. Some wants to sell them to other collectors in private auctions, some wants to sell them to the highest bidder and give the money to the family and/or donations. But they fear that their relatives with little knowledge of the collections value will do things they wouldn't approve of."

"When you sell something at auctions, there is a sellers commission, so wealthy collectors often negotiate with auction houses to sell their entire collections with lowered commission fee. This is where you see most crazy stuff, because you go to visit these people so see their collections with them and agree upon a deal. Some people have the most mind blowing stuff laying around. And some of them have very strict rules for whom they want to sell to and especially whom NOT to sell to."

"The classic examples are the very German sounding last names with art from earlier Nazi occupied nations. Dutch names with Malaysian art. British names with Egyptian, Chinese and Indian art. Religious leaders that buys and sells their own religions artifacts. Political party leaders that buys and sells things strict in opposition to their 'beliefs'. Royalty from all parts of the world buying the most random things."

"What makes me sad is, when people buy things that they collect with the intent of humiliation. Examples are anti-something people who buys things their 'enemies' loved to collect it as trophies. It is very difficult to mention a hypothetical example without sounding biased. Just like Hitler wanted to make a museum with artifacts of his enemies, all kinds of people do this to this day. Lots of people has middlemen as buyers to cover their tracks, but no one is stupid in this business."

- Antieque

"After today, the largest Triceratops skeleton ever discovered."

"It was sold to private collectors. Robbing scientists of the chance to take a look at the specimen."

- Ghost_Of_Hallownest

"Ethics aside, f*ck that would be cool to have as a Halloween decoration lol."

- ravenousmind

"So not technically hidden anymore, but a few years ago the Vatican uncovered these chambers of rooms on their property that were intricately painted in a style of Western art that is entirely unique and was lost for the last 1000 years. You can probably picture the unique styles of a Roman mosaic, a medieval triptych, and a Renaissance painting--well, this was something completely different, a lost, orphaned branch of Western art that petered out and was accidentally sealed in a room for centuries."

"On my last tour there, the guides showed us this room and said basically, 'Hey we finally got around to cleaning these rooms, take a look around if you want. It represents a lost branch of Western art that exists nowhere else in time or space, if you're into that, whatever.'"

"I was blown away. It was delicate, colorful, more earnest and simple than most medieval art, lots of floral patterns, almost geometric. I wonder if it was never popularized because the Vatican at the time wanted a more brassy, imperialistic style. And there could be more lost artistic experiments like this, sealed off for centuries because the Vatican hasn't gotten around to de-cluttering yet..."

- lemontreelemur

"The Vatican has a ton of historians and archeologists on staff because there's hundreds of rooms, most of them buried or in ruins under the soil, that still need to be explored and researched. Many of them are merely extensions of existing buildings that for one reason or another were walled off and forgotten at some point."

"The Vatican archives have all kinds of interesting stuff too, and they're working towards making a lot more of it publicly available. I'm amazed any of that stuff survived the multiple sackings of Rome."

- RealArby

Art collecting is definitely meant for the rich elite who pride themselves on having such incredible amounts of money. It's a shame that these incredible works are going to continue to circulate amongst those select few.

It's hard to think of it as even being art if no one is around to admire it.