Reddit is officially 15. The site where some of the most devoted, obsessed internet denizens hang out was created on June 23, 2005.

While there are plenty of controversies on the site, it's also good for lots of things: surfacing news, learning weird facts, even soliciting advice. But it's a great spot for mysteries and, well...weird, kind of creepy stuff.

To celebrate Reddit's big day, we rounded up 15 of our favorite mysteries surrounding the site. Some of which are solved, some of which aren't, many of which are kind of disturbing. And, as with anything on the internet, they might've been elaborate hoaxes. But sleuthing around, trying to figure out the truth has always been part of the fun.

OK, here they are, 15 great Reddit mysteries.

1. The Bridge

It's hard to explain, exactly, what The Bridge mystery is. It's utterly strange, though, and there's photographic evidence.

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2. A landmine mystery that Mashable figured out was a prank

Long story short, this dude tricked Reddit into thinking he accidentally killed himself with a landmine.

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3. Coffin in the driveway

I mean... it's a coffin... that showed up in a driveway.

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4. Wi-Fi underneath a concrete pad

Some of the potential answers to this weird situation are kind of dark. In general, it's just super strange.

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SEE ALSO: Reddit turns 15: The dramatic moments that shaped the internet's front page

5. Mom poisoned me

This person apparently solved what happened. It was bad. Really bad.

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6. Guys posts about doing crazy drug. Comments "Google.com how normal again stop now." Then disappears.

Hopefully, this was just a prank. A poster asked about doing Datura, a potentially lethal drug on the r/drugs subreddit. He said everything was fine but later commented "Google.com how normal again stop now" and then never posted again.

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7. No idea if it's real, but an iconic "Glitch in the Matrix" post

At the very least, this is interesting fiction.

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8. Person finds a SIM card and recording device after blowing a fuse. Never posts again.

It seems someone was possibly watching them.

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9. A creepy, creepy, CREEPY sleep recording

Listen to the recordings at your own peril.

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10. This is either a creepy unsolved mystery or good short fiction. Either way, a good read.

TL;DR a creepy couple followed this hiker for many miles, in the dead of night. But you should read it all.

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11. Person finds a random box. What's inside it is WILD.

The top theory is the owner of the box went a little nuts trying to find evidence of aliens in the Bible.

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12. A hero steps in to find this person a song

"Shh baby is ok," is instantly iconic.

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13. Reddit, sadly, helped identify a mysterious missing person case known as Grateful Doe

A whole subreddit devoted itself to a missing person's case and helped figure it out.

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14. Not totally a mystery, per se, but a conundrum.

The neighbors are assholes, sure, but maybe pulled off a perfect crime?

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15. No, we never got an answer about this. Yes, it is creepy. Sorry.

The picture sort of speaks for itself. Extremely Purge-y.

Reddit