I'm traversing the Northern shore west of Solitude, past the fort where the High Elves are located on the coast. I come across this:

http://i126.photobucket.com/albums/p117/arkanSTFU/ScreenShot310_zps4b278641.jpg

http://i126.photobucket.com/albums/p117/arkanSTFU/ScreenShot311_zps94f3171a.jpg

It looks like it leads into a cave...but I've never run into this before. I Googled, but the closes place I could find that fit the description was Lost Echo Cave, but that's not accessed from this location. Could this be from a mod?

I'm not familiar with that exact spot but there are a couple of unnamed caves like that. What was inside?

Oh, yeah, that's the thing. There is no actual entrance. I suspect it has something to do with the brazier, but I have nothing in my inventory that will activate it.

I'm willing to bet it's from a mod, but which one? Interesting NPCs?

It's not from a mod. It's the Lost Echo Cave

http://www.uesp.net/wiki/Skyrim:Lost_Echo_Cave

It looks like an alternate entrance to Lost Echo Cave based on the map. Do you have Glowing Mushrooms on you?

EDIT: Actually, it looks like it's far from LEC. I'm doing some snooping.

It seems like a mod as I don't remember "activating" braziers but it's been a long time since I've explored the entire land.

The brazier is definitely not Vanilla(bring up the console and click on it to check what mod it came from), but that "cave" is.

Judging from the trail leading to it, I'm guessing it's meant to be a "road" through the mountains that leads into High Rock, but isn't implemented for obvious reasons. Sorta like http://www.uesp.net/wiki/Skyrim:Southfringe_Sanctum. Or http://www.uesp.net/wiki/Skyrim:Tolvald%27s_Cave

I looked at the area ingame, on UESP map and through the CK. Didn't see anything.

Looks mod related, but I could've missed something.