Does having something “unverified” count? Because I’d like the theory that Sappho cribbed everything she ever wrote from the works of Homer disproven. Of course, we would have to have the complete works of both to do that, wouldn’t we? 
What exactly happened to that cherry tree.
A home video that captures the rifle shooting from the sniper’s nest on the sixth floor of the school book depository would be nice.
Marilyn Monroe’s suicide.
In the 1840s a slave named Stephen Bishop explored a substantial amount of Mammoth Cave in Kentucky. He (and two other slaves who accompanied him) left their signatures in candle smoke throughout the cave system as they explored. Modern spelunkers claim to have found these signatures in places they found quite amazing and arduous, even with modern equipment.
I’m not a spelunker, nor knowledgeable about it, but am curious. Several years ago I took a tour of Great Onyx cave, about 5-6 miles away from Mammoth. One guide claimed to have seen Stephen Bishop’s signature(s) deep within the Onyx cave, past the legal limit* of travel. And that these only appeared deep within the cave, nowhere near the entrance.
So, are Great Onyx and Mammoth Cave actually connected? And did Stephen Bishop discover this in the 1840s using only lanterns? If so, he’s even more impressive than I realized.
*Caves are “owned” by the landowner above. Without permission, it’s supposedly illegal to explore past the property lines of the aboveground owner. Or at least that’s what I was told.
I’d like proof of Plutarch’s account of Cleopatra being smuggled inside a bed sack to meet Julius Caesar. A verified love letter from Caesar to Cleopatra would suffice:
Dearest Cleo, Queen of my Heart,
Hey Toots, I loved bumping uglies with you last night, you foxy mama! Unwrapping you from the rug you arrived in got me horny with desire. Sorry about the rug burns on your keaster, LOL! Please accept my gift of the enclosed asp as a gesture of my enduring love for you, babe. Maybe someday you’ll find a use for it.
Yo, how’s about you, me and my man Markus do a threesome some night! He’s hung like a Nile Croc!
Your Roman Stud-muffin,
Jules
Yes, Gaius Julius Caesar spoke American slang.
Meriwether Lewis (of Lewis and Clark fame) died under mysterious circumstances. It is presumed to be a suicide, but he was shot multiple times.
That would do nicely!
A more entertaining document would be one somehow proving that Edward de Vere was in fact a wholly fictional character invented by Christopher Marlowe as a practical joke. Or the other way around. Whatever settles it.
In John Adams’s autobiography, he wrote about sharing a tiny bed in a tiny room with Benjamin Franklin in 1776. They quarreled. That amuses me. They were the original Odd Couple.
But, I would like to read the uncouth Oscar-like Franklin’s account of sleeping with fussy Felix-like Adams. That would be comedy gold.
Re: Mozart & Beethoven.
I would not be surprised if they met at the end of a concert given by Mozart. For 30yo Mozart, seeing yet another ‘child prodigy’ based on his model was probably nothing to remark on. And for Beethoven, perhaps Mozart was… unimpressive… in person and he, Ludwig, kept quiet about it.
(This is all supposition, of course, but would explain the lack of a historical record even if they DID meet.)
In 1777, Wolfgang wrote his 10th piano concerto, for two pianos (K365), and the debut was with his sister, Marianne. I like to imagine that Wolfgang was gallant enough to give her first piano, and if I had a historical ‘fact’ to verify, that would be it.
The rest of you can report to this thread on your viewings of moments in WW1, Jesus, etc. I want to see Wolfgang play with the one person who most inspired him to music, the person who helped him write his first symphony, the person with whom he would, for hours, improv four-handed duets at the piano.
I want to see both of the Mozart children play.
I have known of the above painting for 30 years and JUST NOW noticed that Wolfgang is sitting on a cushion and Nannerl is not. 
Was Abraham Lincoln gay (or bi)?
On April 15, 1837, Lincoln arrived at Springfield, the new state capital, in order to seek his fortune as a young lawyer whereupon he met Joshua Speed. Lincoln sublet Joshua’s apartment above Speed’s store becoming his roommate, sharing a bed with him for four years, and becoming his lifelong best friend. Although bed-sharing between same sexes was a reasonably common practice in this period, it is unusual for it to have occurred over such a prolonged time. This has led to speculation regarding Lincoln’s sexuality although this evidence is circumstantial.
And
On March 30, 1840, Judge John Speed died. Joshua announced plans to sell his store and return to his parent’s large plantation house, Farmington, near Louisville, Kentucky. Lincoln, though notoriously awkward and shy around women, was at the time engaged to Mary Todd, a vivacious society young woman, also from Kentucky. As the dates approached for both Speed’s departure and Lincoln’s own marriage, Lincoln broke the engagement on the planned day of the wedding (January 1, 1841). Speed departed as planned soon after, leaving Lincoln mired in depression and guilt.
Plus
Commentary on President Abraham Lincoln’s sexuality has been documented since the early 20th century. Attention to the sexuality of public figures has been heightened since the gay rights movement in the late 20th century. In his 1926 biography of Lincoln, Carl Sandburg alluded to the early relationship of Lincoln and his friend Joshua Fry Speed as having “a streak of lavender, and spots soft as May violets”. “Streak of lavender” was period typical slang for an effeminate man, and later connoted homosexuality.[9] Sandburg did not elaborate on this comment.[10]
Not that it matters…
The identity of the Zodiac Killer comes to mind.
I’d like to know the circumstances surrounding Abe “Kid Twist” Reles going out the window. The mob turncoat was set to testify, and was guarded 24-7 by police in a Coney Island hotel, and fell to his death.
I’d like to know if the Nazis really did bury a bunch of gold (link).
I know Maura Murray seems to be THE disappearance people want solved although there are many others that are weird enough that they pique the curiosity of true crime curious. For me it is the disappearance and death of Kris Kremers and Lisanne Froon. It is just a rabbit hole of mysteries from the missing picture 509 to the last series of pictures taken. How exactly did they get lost OR maybe they didn’t get lost. Maybe they were followed or even forced to travel a certain direction.
I did a deep-dive into that last year. Looked at all the photos. There’s so much that doesn’t make sense. It still bothers me.
Perhaps…but.
Beethoven’s student Carl Czerny, reports Beethoven describing Mozart’s playing as “fine but choppy, and without much legato.” But, at age 16, I can’t imagine Beethoven not being impressed with a mature Mozart performance, unless he gave a particularly poor performance due to illness. After all, Beethoven’s goal in Vienna was to take lessons from the greatest living composer—Mozart. And he did study and absorb his style.
Leopold failed in nurturing Ludwig into a child prodigy, like Mozart. But still, at 16 Beethoven was certainly a top-notch virtuoso and published his first composition at age 12. I believe Mozart would have been impressed with his playing and budding compositional skills, had he heard him play.
I wish more of Wolfgang’s 6 children survived infancy, in hopes one of them inherited Dad’s genius.
Like I said, my supposition was that: mere supposition about one way they could have met and come away unimpressed.
Hell, forget about Wolfgang’s kids. Anna Maria gave birth to five additional Wolfgang siblings, seven children in total, and only Wolfgang and Marianne survived. Whatever Leopold Mozart’s fault as a person were, the man was a damn genius at teaching his kids and I wish he had more kids to teach!
I agree, Leopold did an excellent job homeschooling his kids. And Wolfgang could not have nurtured his kids the same way, mainly due to death and all (deadbeat father!). Maybe they could have taken lessons from Beethoven. That would have been a kick in the pants!