In the days before we had advanced science to help us figure things out, we employed a pantheon of gods and goddesses to explain the more perplexing puzzles of the universe. Crazy thunderstorm? Zeus must be in a tizzy. Fast forward to the present and we've developed all kinds of technology to help us unlock mysteries that were once considered magic. But Mother Nature isn't willing to reveal all her tricks so quickly, so we have to figure them out for ourselves. Case in point? We've got eight of them right here. From a waterfall that disappears into nowhere to odd jelly blobs that fall from the sky, the mechanics behind these natural phenomena are some of nature's best kept secrets.

1 of 8 Singing sand dunes Photo: Nepenthes /Wikimedia Commons Um, so, yeah ... the Earth is singing! Well maybe not the planet itself, but a number of sand dunes across the globe — in at least 35 deserts from California and Africa to China and Qatar — are definitely making some intense noise. Sounding like a deep hum of bees or some rumbling Gregorian chant, the moaning mountains have baffled scientists for years. One study discovered that different notes produced by the sands relied on the size of the grains and the speed at which they whistle through the air, but scientists still have no idea how the flowing grains of sand manage to sound like music in the first place. Have a listen below:

2 of 8 Star jelly Photo: James Lindsey /Wikimedia Commons Reports of globular blobs falling from the sky and plopping into fields and meadows date back to at least the 14th century. Also known variously as astral jelly, star-shot, star-slime, star-slough, star-slubber and star-slutch, folklore explained the curious goop as a substance deposited after meteor showers. If not frequent, reports of the mysterious goop occur with a surprising degree of regularity. But nobody can say for sure what it is, as it dissipates relatively quickly after it appears and analysis has been challenging. Speculation has ranged to everything from the paranormal to unknown fungi or slime molds to something of an amphibious nature, but no succinct identification has been confirmed by science.

3 of 8 Ball lightning Photo: Wikimedia Commons /Wikimedia Commons We all know that lightning comes in zigzag bolts that strike from the sky. Except when it doesn’t, like, when it comes in a big circular glowing blue flash. Such is the weather phenomenon called ball lightning (which doesn't really streak indoors like the fanciful illustration here suggests). It’s rare and hard to predict, and because of that, researchers don’t know much about it. It can last for more than a second, which is long for lightning, but still ... it’s hard to capture a second-long flash of light to study in the lab. Explanations have ranged from electrically charged meteorites to hallucinations induced by magnetism during storms. One theory is that when lightning strikes something it explodes in a cloud of highly energized nanoparticles, notes the Weather Channel, but for now that remains just speculation. If only we could ask Zeus.

4 of 8 Catatumbo lightning Photo: Thechemicalengineer /Wikimedia Commons While ball lightning is known for its infrequency, Catatumbo lightning is famous for just the opposite: its astounding prevalence. Occurring over a swamp in northwestern Venezuela almost every evening for centuries, this "everlasting storm" averages 28 strikes per minute in events lasting up to 10 hours. When things really get going, lightning strikes every second. Oh, and the lightning is colorful. And does not produce thunder. And sometimes just stops for a few weeks at a time. What the heck? To be certain it has inspired plenty of speculation. The only answer so far is that it's produced by a perfect storm, so to speak, of topography and wind. Hmmm.

5 of 8 Crooked forest Photo: Artur Strzelczyk /Wikimedia Commons There was a crooked man, he walked a crooked mile ... but did he walk in the crooked forest? This groovy grove of trees in West Pomerania, Poland is a weird wonderland of some 400 pines that took a definite detour in the ol’ “growing straight as a tree” routine. Nobody has any idea why. Adding to the mystery is the fact that they are part of a larger forest of normal unswerving pines. What is known is that they were likely planted in the 1930s and whatever caused them to waver in their sky-striving happened when they were seven to 10 years old. Theories abound, but until trees can talk, we may never know the real story.

6 of 8 The Wow! Signal Photo: Ohio State University Radio Observatory/North American AstroPhysical Observatory /Public Domain Back in 1977, Jerry Ehman was scanning radio waves from deep space as a volunteer for SETI, the Search for Extraterrestrial Intelligence. At one point, his measurements spiked with an uncanny signal that lasted for 72 seconds. It seems to have come from within the Sagittarius constellation, which lives by the star Tau Sagittarii, a mere 120 light-years away. Ehman wrote the words “Wow!” on the original printout of the signal, and it’s been known by that appropriate exclamation ever since. So what's so wow-worthy? As National Geographic notes, “the signal that was received was at precisely the right frequency that wouldn’t be interpreted as noise, and wouldn’t be intercepted along its journey. In other words, if we were going to send a signal out into the universe to try to communicate with an alien race, that’s exactly the frequency we would use.” Since then, despite much effort, the signal has never been heard again. Ow!

7 of 8 Devil's Kettle Falls Photo: Roy Luck /flickr The Brule River goes about its usual river business winding through Minnesota, but while traveling through Judge C. R. Magney State Park, it takes a very, very strange turn. Over the course of 8 miles, the river drops 800 feet in elevation forming several waterfalls along the way. At one point, a large jutting rock formation splits the river, resulting in two waterfalls. One side does the typical waterfall thing, but the other side falls into a hole known as the Devil's Kettle. And then, it just completely disappears, a mystery that has been baffling visitors and scientists for ages. Common sense would suggest that the water reappears somewhere in nearby Lake Superior, but researchers have tried every trick to locate the missing water — including dying the water and adding ping pong balls — to no avail.