If you’ve played The Elder Scrolls V: Skyrim, you know just how creepy it can be. Whether you’re fighting restless spirits, fleeing from insane cults, or turning yourself into a werewolf through blood rituals, you’re bound to come across strange, creepy things in Skyrim.

However, you might still be missing out. Thanks to its huge map, Skyrim harbors many dark secrets—particularly in its dungeons. A small, hidden cave entrance could actually hold an entire underground city. Outcasts like criminals, vampires, and witches tend to hide in caves, and they perform bizarre, disturbing rituals.

Every dungeon on this list is difficult to find. Most are easier to find on your map than with your eyes—but your map can’t always help you. Several creepy dungeons hide at the borders of Skyrim, and some aren’t even marked on the map. Only diehard explorers find these unmarked locations, but they’re immensely rewarded—if they enjoy creepy stories, that is. All these dungeons are creepy on the surface, but some host even creepier stories in journals and secret rooms.

If you want to immerse yourself with horror stories and unsettling monsters, look no further. These 15 Skyrim dungeons will haunt you long after you complete them.

15 The Midden

The College of Winterhold hides many dark secrets, particularly in its “basement,” known as the Midden. Hidden trapdoors lead to the Midden, where you’ll discover dead College students, strange magical artifacts, and terrifying monsters.

While you’ll discover parts of the Midden through quests, you must explore to find the Midden’s creepiest secrets. In one corner of the Midden, four bodies surround a creepy gauntlet. If you search for clues, you learn that four students tried a dangerous summoning ritual and died in the process. You can perform the ritual yourself, which summons a Daedra that admits he murdered the students. As their four skulls orbit the gauntlet, you may either avenge the students or accept a reward for summoning the sadistic Daedra.

14 Mara’s Eye Den

The icon for Mara’s Eye Pond suggests it’s an outdoor location. A small island rests in the middle of the pond, forming the pupil of Mara’s Eye. A small, half-submerged boat sits abandoned on the island’s shore. At first glance, this seems like the only significant part of the location—but a dungeon actually lies beneath the pond.

If you swim to the island, you’ll notice a trail of blood leading away from the boat. A hidden trapdoor waits at the end of the trail. Inside you’ll discover Mara’s Eye Den—a cave in which two vampires live.

Several crates sit within Mara’s Eye Den. They look harmless, but they’re actually filled with corpses. A journal notes that the vampires smuggle bodies into their den, allowing them to consume people without ever stepping outside.

13 Shriekwind Bastion

Though Shriekwind Bastion hides in the southern mountains of Skyrim, explorers have a higher chance of finding the dungeon thanks to its two entrances. However, you may miss the secret within the dungeon.

Shriekwind Bastion features so many unique landmarks that a lot of people miss its secret closet. A massive wall dominates the underground dungeon, with skeletons patrolling the wall and vampires waiting within the caves. Because of the natural skylight above the wall, a single tree grows in the dungeon’s depths. Players preoccupied with the wall and the tree miss the closet, which houses multiple pairs of shoes.

Based on the inhabitants of Shriekwind Bastion, I assume those shoes belonged to the vampires’ victims. The creepy, sad closet reminds us that vampires murder countless people in order to survive.

12 Darklight Tower

Despite its height, the Darklight Tower is easy to miss. The tower hides within the southeastern mountains of Skyrim, blending in with the gray rock around it. If you’re lucky enough to find it, you’re rewarded with an entertaining, creepy quest. Hagravens and witches occupy the tower, performing bizarre rituals like sacrifice.

Most dungeons with hagravens are straightforward, but in Darklight Tower you find a friendly face. Illia—who recently joined the cult alongside her mother, Sylvia—hates what she sees. She wants to end the evil rituals in Darklight Tower and kill everyone in the tower, including her mother.

To catch the witches off guard, Illia asks you to be a decoy. You pretend to be an ignorant sacrifice and let Sylvia lead you to a chair. This wonderfully finishes the creepy quest, making you a sacrificial victim just before you and Illia kill the witches.

11 Pelagius’s Mind

If you’re lucky enough to discover the “Mind of Madness” quest, you’re rewarded with a normally inaccessible location. After entering the Pelagius Wing, where Pelagius III resided long ago, a mischievous Daedra named Sheogorath teleports you inside of Pelagius’s mind.

People called the emperor “Pelagius the Mad” and “the Mad Emperor”—and for good reason. Creepy illusions and paranoias await within Pelagius’s mind. Sheogorath (who waits at a banquet reminiscent of the Mad Tea Party) teaches you how to cure Pelagius’s insanity. However, your actions seem to only worsen Pelagius’s condition. You “cure” his paranoia by turning men into bloodthirsty wolves, his nightmares by summoning monsters, and his anger issues by turning “Confidence” into an overgrown man who destroys anyone in his path. You leave Pelagius worse off than when you left him—making you wonder if Pelagius was truly mad or if you’re the one who destroyed his sanity.

10 Angarvunde

When you enter Angarvunde, a Dark Elf named Medresi Dran tells you of a great treasure. If you agree to help her, you eventually unlock the treasure room alongside her. She rushes in—and dies in a trap right in front of your eyes.

The developers use Medresi Dran to creepily warn you of traps—although they teach this lesson in an odd location. Angarvunde hides in the southeastern corner of Skyrim, nestled within a group of mountains. Only true explorers find themselves at Angarvunde, but they’re greatly rewarded for their efforts. After avoiding Dran’s body and the trap that killed her, you’ll discover a treasure chest and a Word Wall. Too bad Medresi will haunt your memories whenever you use that Shout.

9 Kagrenzel

Kagrenzel rests at the eastern border, deep within the mountains. If you find the Dwemer dungeon, you’re immediately greeted with a creepy sight. Entering a massive room, you see an orb of light in the middle of the room—along with two corpses next to the orb.

If you’re brave or stupid enough to touch the orb, a cage pops up around you, trapping you with the bodies. The orb blares like an alarm before slipping into the floor. The floor flips, dropping you into a deep, narrow hole. Surviving the fall is difficult, but if you’re careful you’ll fall harmlessly into a pool of water at the bottom.

The following dungeon is incredibly fun, but the deadly entrance is horrifying. If you’re a Khajiit, beware: curiosity kills.

8 Lost Echo Cave

Tucked away in the northwestern corner of Skyrim, Lost Echo Cave seems like an insignificant tomb at first glance. Glowing Mushrooms line the tiny, empty cave. However, the cave harbors a secret. A book states that a mighty lord wanted a humble burial, so his followers buried him here as a reminder that “we all return to the same ground from which this mushroom blooms.” This philosophy is also a riddle: if you burn a Glowing Mushroom in the cave’s ceremonial brazier, you unlock a hidden passageway.

If you follow the passageway, you discover a group of hostile Falmer. The cave creepily says we all die before trying to murder you. The lord’s tomb is in fact a graveyard for anyone who ventures into the cave.

7 The Reaper’s Lair

The Reaper’s Lair lies within Soul Cairn, a hellish afterlife in the Dawnguard DLC of Skyrim. Soul Cairn is already creepy, but the Reaper’s Lair harbors dark secrets. Multiple characters indirectly refer to the Reaper, expressing great fear for the keeper of the dead. To meet the Reaper, you must locate his Lair and place three Reaper Gem Fragments within the Lair—at which point the Reaper rises and attacks.

Several towers with beacons of light exist within Soul Cairn; the Reaper’s Lair, on the other hand, hides in a tiny, unlit fort. Strange lightning strikes within the fort, making you feel unwanted as soon as you step inside. The Reaper reinforces this feeling: his red eyes, inhuman body proportions, and executioner’s clothing are absolutely terrifying. No living soul belongs in Soul Cairn, but particularly not in the Reaper’s Lair.

6 Ilinalta’s Deep

Nearly all of Ilinalta’s Deep has sunk into Lake Ilinalta, making the fort incredibly difficult to see. The fort blends in with the dark lake and the gray mountain behind it.

If you’re brave enough to venture into an underwater fortress, you’ll discover creepy scenes from beginning to end. A crucified skeleton greets you at the entrance, Malyn Varen’s skeleton sits in a chair at the end, and a cult battles you in between. Beside Varen, you’ll discover the Broken Azura’s Star and a journal. Apparently, Varen ran experiments to become immortal—experiments which actually led to Ilinalta’s Deep sinking into the lake.

In the questline that follows Azura’s Star, you eventually learn that Varen trapped his soul within the Star. This sheds a creepy light on Varen’s experiments and the Star, especially since you’ve been unknowingly carrying his soul this entire time.

5 Geirmund’s Hall

Geirmund’s Hall was originally designed as a tomb for a single man: Lord Geirmund. Geirmund died when his three sons murdered him, stole his magical amulet, and tried to conquer Skyrim.

As punishment, the three sons were turned into undead and imprisoned. They were separated into three different tombs—including Geirmund’s Hall. Sigdis restlessly walks the halls of his father’s tomb, forever reminding him of his sins.

Skyrim includes many bizarre criminal punishments, but this is one of the creepiest. Sigdis’s soul lives on within an undead corpse. As if that wasn’t bad enough, he lives in a tomb built for his own victim. I’d laugh at the irony if Sigdis’s angry corpse wasn’t trying to murder me.

4 Halldir’s Cairn

A strange beam waits inside Halldir’s Cairn, as well as three bandit bodies. One of the bandits left behind a journal—which notes that Halldir magically corrupted their minds, convinced them to jump into the beam, and stole their blood and souls so he can rise from the dead.

Most people would run away at this point. If you stay and explore, you’ll discover a lever that opens up the rest of the dungeon. Ghosts and Draugr—obviously servants of Halldir—await, as well as Halldir’s ghost at the end of the dungeon. Thanks to multiple blood sacrifices, Halldir has the unique ability to clone himself. Up to three clones can battle you alongside Halldir, creating a disturbing and challenging battle.

3 Labyrinthian

With mountains on all sides, Labyrinthian hides from all but the most explorative players. These extensive ruins once housed the dragons during their tyrannical rule over Skyrim. That culture still lives within the dungeon, where undead dragon skeletons and Dragon Priests attack any trespassers.

While anyone may access the outdoor ruins, you can only enter the dungeon through the College of Winterhold questline. To complete the questline, you must acquire the Staff of Magnus from Morokei, an incredibly powerful Dragon Priest inside Labyrinthian.

Morokei waits at the end of Labyrinthian, but he speaks to you throughout the dungeon. His creepy, grating voice speaks first in the Dragon Language and then in Nordic, warning you that you will soon die. He steals your magicka every time he speaks, making Morokei an intimidating, terrifying boss before you even encounter him.

2 The Chill

If you fully explore Winterhold, you’ll notice the surprisingly small city lacks a prison. That’s because the prison’s not in the city: it’s far north, hidden within the icy wasteland of Skyrim. The Chill is an unmarked location, so you’ll only find the prison if you stumble upon it or perform crimes in Winterhold.

Because of its location, the Chill quickly kills its prisoners. Only skeletons inhabit the prison made of ice, and Frost Atronachs guard it. Not even a well-prepared human guard could survive in the Chill, yet Winterhold nonetheless sends criminals there to die slow, cold deaths. If you think death row is inhumane punishment, imagine how terrible it would be to die of hypothermia within the Chill.

1 Yngvild

Yngvild rests at the northern end of Skyrim, on an icy island north of Dawnstar. After Dawnstar exiled him for his disturbing necrophilia, Arondil moved into Yngvild. He now uses the cave as a base of operations. He kidnaps young women, kills them, and revives them through necromantic experiments. His journals reveal that he also sleeps with the undead women; if you sneak into his bedroom, you’ll discover a ghost sleeping in his bed.

Female Draugr and ghosts haunt Yngvild, serving Arondil against their will. Fortunately, you can put an end to Arondil’s disturbing experiments by killing him. Even the undead will help you. A pedestal beside Arondil holds a Greater Soul Gem: if you take the Soul Gem, the ghosts turn against Arondil and avenge their own deaths.