51 Legends And Myths Once Considered Hoaxes That Evidence Later Proved True

The Shang Dynasty, China's second dynasty according to traditional historiography.

Until the 20th Century, there was no direct evidence that it had existed besides records describing it left behind by dynasties that came centuries after them, and it was ascribed semi-mythical status.

Then one day somebody realized that "dragon bones" being ground up by a bunch of villagers to make medicines were actually oracle bones, the first direct written evidence of the Shang Dynasty's existence left by the dynasty itself.

The dynasty preceding the Shang, the Xia Dynasty, is still considered mythical, and since it precedes writing its existence is harder to verify.

Edit: Archeologists have however recently found evidence of a massive flood on the Yellow River 4000 years ago that has been suggested to correspond with the Great Flood of the Xia Dynasty's founding myth.

Ball lightning is pretty fascinating.

There have been anecdotal reports of it for hundreds of years, but it was hard to document because it doesn't last long and it couldn't be photographed. It's also hard to create it in a lab. But it is acknowledged now that it does exist.

I first read about it in one of the Little House on the Prairie books and thought it was wild. I wasn't sure if it was real or some kind of hallucination.

Rogue waves were once considered tall tales told by sailors and captains were shamed if there ship was damaged or sunk by them. Now they are studied by scientists.

For a few hundred years the Micronesians, a stone-age culture, had the fastest sailboats in the world. The first few reports of how fast the boats went were derided as fantasy. It wasn't until George Anson made actual measurements and drawings in the 1740s it was taken seriously.

Atoms were first thought of by Ancient Greek philosopher Democritus. He called them "atomos" which meant smallest part. It took over 2000 years before he was proven right. During his time people believed the four elements were still earth, wind, fire, and water.

Germ theory, the man who conceived the idea was dismissed and treated like a lunatic. 'There are millions of tiny invisible creatures all over and inside us that make us ill?' Preposterous!

NSA spying on literally everyone all the time.

Cups of microwaved liquid apparently exploding, aka Superheated Water. When it first was reported it no one would believe it - people getting scalded when they take an apparently still, non-boiling cup of liquid out of a microwave and have the contents suddenly burst up out of the container.

It's now well-documented and the mechanism understood..

For a long time, the only knowledge to the Hittite civilization was their reference in the Hebrew Bible. Turns out they were a pretty big deal in what is now Turkey.

The mole man of edge hill in Liverpool uk, if I remember right the was a myth about a rich guy who built a massive tunnel network under Liverpool and lived down there. Turns out he did and he did it all because of mass unemployment, he was rich dude who did not want to see all the people out of work so he hired them to build a network of brick tunnels under his house, later he went a bit crazy and lived down there. The people who built the tunnels then went on to build all the train tunnels in Liverpool, which some actually intersect the mole mans tunnels and you can see where they have been bricked over.

The eruption of Vesuvius in 79AD. When Pliny's account of the eruption was first found by Victorian's, none believed such a 'fanciful' tale. Only with modern reconstructive science and study of the geology do we know that his account was mostly accurate.

The Pygmy Hippo

For years it was considered a myth - scientists believed it was just a legend told by the local tribes. And then a few years back, look how cute that guy is!

Prion diseases like mad cow and fatal familial insomnia and kuru.

They are caused by a protein malformation and yet are communicable, which was thought to be impossible by epidemiologists. And yet here we are with prion diseases caused by genetics (fatal familial insomnia), by consumption of brain tissue (mad cow, kreutzfeld jacob, kuru) and now by pathogen (chronic wasting disease).

Not quite a myth but Jonathan Swift wrote in Gulliver's Travels (1726) about Mars having 2 moons about 150 years before they were discovered (in 1877). He got their distances from Mars and orbital periods not ridiculously wrong, either.

The Okapi was once thought to be a fake. Turns out it wasn't. Just like many other animals before the modern age, if you didn't have its hide (or a live specimen) to prove it, it was assumed fake.

A boiling river in the Amazon. tl;dr of the story as I heard it on Weird Wonders of the World:

Back in conquistador days Spanish explorers went into the jungle. When they came out one of the many stories they told was of a boiling river that k****d any living thing that fell in. Some guy heard these stories growing up, went into geology, and asked around about it. Nobody in academia knew of any such river so he gave up. He mentions the topic among family in a "too bad it's not real" way and his aunt says "but it is." She takes him to some locals and he takes a trip to see it. It totally is and it *is boiling*, not just pretty hot. It's way hotter and larger than anything else in the area and they're not sure yet why/how that much geothermal activity is going on at that spot.

Jade burial suits from ancient China were thought by archaeologists to be myths until actual suits were found in the mid-20th century.

A black swan.

It used to be a saying 'hunting for a black swan' meaning a futile attempt to look for something that doesn't exist.

When the black swan was discovered in Australia, the saying changed to mean something everyone thought didn't exist, but in fact does.

In Portugal, I can't remember where exactly, there was this tradition where every year the local priest would bless a batch of bread. That bread would then be kept in a closed chest, in church, and would be given only to people who were ill. The bread would only be replaced the next year, so if you were unlucky enough to get ill 8 months after having the bread blessed and stored, you would be given moldy bread.
This however proved to be effective sometimes, actually saving people's lifes (though not by direct Divine intervention), for the mold in the bread would fight infections just like penincilim.
I always found this story quite fascinating.

Kangaroos were once classified as Cryptids (along with Bigfoot, Loch Ness monster, etc.)

Before it was established that they kept their babies in their pouches, it was told that they were "creatures with two heads". Makes me think what other cryptids we actually are just seeing wrong.