The full nine hour cut of Erich von Stroheim’s Greed.
Also, I read a lot about art theft and forgery. There are a TON of great stories to be had in the art world and I recommend the book Museum of the Missing for anyone interested in an expansive survey of the topic.
Could we include the mysterious Missing Sock? 
Fascinating thread.
The Ark of the Covenant may actually be still out there, hidden.
I was doing a google search for “the Lost Monet” and ran across this news article from a couple of years ago listing a few missing paintings:
Art Masterpieces Still Missing (Monet to Matisse)
ETA: list on page 2.
The Portrait of Dr Gachet by Vincent van Gogh. The last definitive location of the painting was in 1990 when it was purchased at an auction by a Japanese billionaire, Ryoei Saito. Saito died in 1996 and it’s not known where the painting is. One rumor is that Saito or his heirs sold the painting to someone who wishs to own it anonymously. A more disturbing rumor is that Saito had the painting destroyed - he once said that he planned on having it cremated with him when he died.
In the Wash, an estuary fed by several rivers, rather than a river itself.
Mata Hari’s skull.
My keys, I know I left them around here somewhere?:smack:
This article and this one has a good list.
Christ’s foreskin. According to Richard Zacks’ An Underground Education, there was quite the massive search for it during the Crusades. Crusaders somehow came up with plenty of fakes, though…
Huh? They found all kinds of debris and about 50 bodies.
80% of the universe. (aka “the missing mass”)
Changa’s white boots.
The original film of the moon landing
Perfect circles, three-sided squares…
Fertmat’s Last Theorum
The Lost Chord
I think we can safely assume that this was never saved in the first place. I mean, I know mothers hang on to baby booties and things like that, but surely first-century Jewish parents didn’t save their sons’ foreskin, right?
The full version of the original *The Wicker Man *[1973]. They think the lost footage (IIRC, 40+ minutes’ worth) got buried under an English highway then under construction.
As a warning to other movies that might be thinking about testifying against British Lion Films.
Does a Prime Minister qualify as an object?
