The hardest cave on The Island is the Snow Cave, formerly known as the Ice Cave. What makes this cave harder than all the others on The Island? The temperature in the cave ranges from -18 degrees at the entrance to -30 degrees at the Artifact chamber. The temperature drops by 5 degrees while in the water of the cave, and you also will take 6 damage every 2 seconds while in the cave's water. Creatures in the cave include, but are not limited to, Direwolves, Polar Bears, and Purlovias that spawn up to 2 times the server level cap. You NEED at least Journeyman Fur armor, and if possible, an Otter on your shoulder. If you have a Cryopod and a high-level Yutyrannus, that would also be useful, but you can't deploy the Yutyrannus until after the crawl point. After the crawl point, you can bring the Yutyrannus through the entire cave, all the way to the Artifact! The Artifact of the Strong is located in this cave, needed to summon the Dragon boss.

The Jumping Puzzle is the hardest cave on The Center, and it consists of multiple parts. First of all, is is cold, but not Snow Cave level (usually around 0 degrees), however it is much hotter in the Artifact's actual chamber (usually around 35 degrees). The cave's difficulty does not directly come from the environmental dangers, but rather the spawns (Araneo, Arthropluera, Onyc, Pulmonoscorpius, and Titanoboa that can spawn up to 2 times the server level cap). This cave also connects to the Underground World. There are two entrances:
-53.5, 53.8 (Land entrance)
-66.1, 51.7 (Underwater entrance)
The Artifact of the Pack, needed to enter The Center's boss arena, is found in this cave, however there is a tricky path ahead of you! You can't just go into the Artifact's chamber, seize the Artifact, and leave, you have to do a hard parkour course-over lava! Specifically, the Artifact's chamber has no spawns, but you have to instead do a near-impossible parkour course over a pit of lava, and you can't use grappling hooks to aid you! You also can't bring a flyer or climber into the chamber-they will hit an invisible wall if they try to enter! However, if you port one in from another map, a Shadowmane can enter the chamber and charge-jump right to the Artifact! You could also use a zip-line or climbing pick because they are not grappling hooks.

The hardest cave on the desert ARK is the Ruins of Nosti, also known as the Church Cave. The cave is located in the south-eastern dunes, so just getting to it is hard! The cave's actual entrance is located inside of a church, giving the cave its nickname. There are large swarms of Mantis and Onycs in this cave, and the occasional Rubble Golem. however, they do not have any higher max levels than their normal counterparts, so they are not the significant threat of this cave. The real threat of this cave is the large bottomless pit that can kill any tameable creature in the game. You can use grappling hooks to completely bypass the jumps of this cave, making this cave significantly easier, of course, besides the Onycs. The Artifact of the Destroyer is found in this cave, needed to summon the Manticore. When you collect the Artifact, then, and only then, will the creatures start spawning! A Thylacoleo can fit through the entrance and climb up the exit ledge to the Artifact, making it the best creature to bring to this cave.

The hardest cave on Ragnarok is Life's Labyrinth. This cave goes back to the 2x server level cap-leveled creatures. This cave is a challenge that few can stand up to, but if they do, they are rewarded with FOUR artifacts! This cave is phase-based and split-decisional, meaning that there are parts of the cave that have two progression advancements, but you can only choose one, unless you are playing on a server and are in a group, eliminating the need to run this cave twice. The first room, and the only room where you can turn back if you do not want to run this cave yet, is a room full of buttons. There are letters above the buttons, and only five can be pressed. The buttons must be pressed in the order that spells out "GRÁTA". The "G", "Á", and "T" buttons are found easily, but the "R" and "A" buttons require some parkour or a TEK Chestpiece, as you can't use grappling hooks in this cave. After you have entered the "password", the floor in the central part of the room will open and you can go into the main part of the cave. Make sure you fall into the water at the bottom of the fall, or you will take fall damage. Advance through the corridor, and a gate at the end will open. The first split-decision room is up next. A statue lies at the back of the room, and if a petrified human or uneven tile is touched in this room, the statue will spit some fire at your group and you and your group will take a lot of damage and be stripped of their armor. There are two exits at the back of the room, on either side of the statue, and the exits are opened by buttons. The left exit is opened by a button in the rubble directly to the right of the statue, above it are the words "We crucify ourselves between two thieves" while the right exit is opened by a button directly to the left of the entrance to the room. The left side will lead you to the Artifact of the Skylord ("Regret for the past"), while the right side will lead you to the Artifact of the Clever ("And fear of the future"). Whichever group pressed the Artifact of the Clever button should get the Artifact of the Skylord, and whichever group pressed the Artifact of the Skylord button should get the Artifact of the Clever.
LEFT SIDE:
"Drowning men will cling to wisps of straw"
Basically, this line will tell you all about this section of the cave. You have to swim through a water tunnel (SCUBA suit advised!) and follow the path with the bio-luminescent seaweed.
"One door closes, another one opens"
This part of the cave is possible the most challenging part of the cave. This part will test your speed (If you have TEK leggings, that would be optimal!) because this part has A LOT of timed doors opened by buttons. Those doors will close after some time, so BE FAST! The exit is on the outer side where the poison grenade trap is, and is opened by two buttons. Then you have to press several buttons to open several doors and open the exit to the next section.
"To perceive is to suffer"
This section comes in two parts. The first part has arrow and grenade traps on the ceiling. Do not walk under the pipes! That is how you trigger the traps. The button to the next part is right at the beginning of the section. The exit will shut quickly so use TEK Leggings to run through! The next part is a jumping puzzle that can easily be skipped with a TEK Chestpiece. At the end is the Artifact of the Skylord, hidden in an area on the left wall.
"To sacrifice one self, that is the ultimate sacrifice"
The sacrifice room (will be explained in after the next section).
RIGHT SIDE:
"Pride goeth before the fall"
A jumping puzzle that has a long fall and a loot crate at the bottom, near the end. You can easily skip this part with a TEK Chestpiece. After that, there is a room that spawn Onycs and at the end, shoots spear bolts at you.
"The only way to get rid of temptation, is to yield to it"
There is a loot crate in the middle that triggers a trap when you get close enough. At the end, there are two buttons, one opens the exit, the other one is, once again, a trap. The exit button is the one closer to the exit on the left.
"Not until we are lost do we begin to understand ourselves"

The image above is a tutorial on how to complete this challenging section of the dungeon, Follow the correct path (Yellow on the map), and once you get to the end, fall down the shaft (Bring TEK Boots!), jump over the trench, and get the Artifact of the Clever.
"To sacrifice little, is to gain little"
The sacrifice room.
SACRIFICE ROOM:
You need to sacrifice a creature or (preferably) a player to continue. If you sacrifice a creature, the left door opens:
"Darkness cannot beat out darkness, only light can do that"
A dark tunnel where you will need the TEK Helmet's night vision and scanning mode. There are stone plates on the ground which summon Onycs. At the end, you enter the final artifact room. However, if you sacrificed a player, the right door opens:
"If you go too fast you might not notice everything."
A corridor that has two loot crates in the middle and walls that close in on you. The walls will not close in on you while in the loot crate area. At the end, there is a button to open the exit.
FINAL ARTIFACT ROOM, SPIRIT DIRE BEAR AND WOLF FIGHT:
After going through a maze, going underwater, and sacrificing your weakest group member, you end up in a cavern (Finally there is no brick/adobe ceiling above you!) full of Megaloceros. Kill one of them and you will summon the bosses of the dungeon, the Spirit Dire Bear and Wolf. They are prone to bolas and net projectiles, so bring them if you have them. They spawn in pairs, in 5 waves, starting at level 50, and going up 50 levels per wave increase, ending at level 250. After beating them, the barrier guarding the Artifact of the Devious and Artifact of the Massive vanishes and you can grab them! The exit to the cave is located at the drain, bring a TEK Helmet and go into night vision mode, as the tunnel to the exit gate is quite dark. The exit gate requires crawling, but is timed, watch out! The cave's final exit is also quite low, but there is no gate, only an opening into the desert.

The most difficult cave on the Aberrant ARK is the Hidden Grotto, requiring a full TEK Suit as you can't use grappling hooks on the map at all. Despite the cave having no radiation or Element water, the main threat of this cave are the Cnidaria that can stunlock you while the Anglerfish and Sarcosuchus kill you. On land, you can fight off Titanoboas, Arthroplueras, and Pulmonoscorpius. However, this cave is, in fact, NOT under the 2x server level cap creature levels, so fighting them off is quite easy! At the end of this cave of vertical cliffs and water tunnels, you find the Artifact of the Shadows. Again, make sure you have a powered TEK Chestpiece, or you will be trapped!

The hardest cave on Valguero, a map with (mostly) easy Artifact caves, is The Lair. The home of the mighty Broodmother Lysrix, The Lair is a dangerous cave with toxic gas (TEK Helmet does, in fact, NOT protect you from it, you will still die near-instantly! Consider bringing a Gas Mask instead) and many Titanoboas (Watch your torpor!) that also spawn at high levels, but this cave takes it one step further and has a 3x server cap level limit! However, this is not without its benefits, as this cave contains THREE Artifacts! A Megatherium will plow right through this cave, provided you have a Cryopod and remember to use it after the first room. After the first Cryopod, you won't have to worry about using it again until you get all the Artifacts. You won't have to use the Cryopod to actually enter the cave with the Megatherium, as the entrance is large enough to fit a Rex. You can also use the Megatherium to kill the Broodmother as the boss takes 4x damage from all sources, and it also does not summon minions. However, the Broodmother can have millions of health as it is not locked to level 1. Multiple can also be present at a time (Most that I've seen is 3!) So make sure your Megatherium is imprinted and has a high armor saddle. Also, make sure it has a strong breeding line. For the cave itself, your Megatherium, so long as it is not at critical health, can fight through this cave and get the Artifacts easily, so long as you bring a Cryopod. The Artifacts of the Pack (needed to enter the boss arena at Gamma difficulty), Immune, and Strong (both needed to enter the boss arena at Beta difficulty) are found in this cave.

The Gloom Grove Temple, entrance location shown in the image above, is the hardest cave on Lost Island, despite not being under any level cap multipliers. There are two artifacts located here. This cave, similar to Ragnarok's Life's Labyrinth, has traps that spawn darts, grenades, and Onycs. The discolored bricks are the pressure plates that spawn the creatures, so try to avoid them. Also, stay on the side of the pipes on the walls, those are arrow traps, and they can't shoot you if you are too close to them. The entrance itself is located between 5 stones in the middle of a lake in Lost Island's swamp. A mountain is directly south. The best creature to get to the cave's main section is a Baryonyx, as there are Piranhas in the entrance area. After that, you will come to a cavern with Araneo and Arthropluera, and due to a bug, the audio will sound similar to when you are underwater. To the left, there is an area with Black Pearl clams, if you want them. The route to the temple itself is either straight into another underwater tunnel or to the right, where there is no water. After going down either path, the audio will adjust, and you can advance on to the temple, which the entrance is actually a hole in the temple's wall. When you enter the temple, there are several hallways and pressure plates. You will eventually reach an area with a double spiral staircase. Once you reach that area, go through the entrance on the left side of the entrance to the room. The Artifact of the Massive is in a room that you can reach by going down the stairs. However, the Artifact itself is behind a gate! The room containing the Artifact has a bunch of pressure plates on the ground, including one that summons two Arthropluera onto the Artifact. The button to open the gate is on the far right side of the room, near a rotting corpse. As the gate will shut after some time, be quick! After you leave the room, go up the staircase opposite of where you came, there is a secret path to the other Artifact. When you eventually reach a gate, turn right around. There is a button opposite of the gate that opens the gate, and you will reach an area containing many barrels. In the immediate next room, you will find a button, press that button, and you will open the room containing the Artifact of the Devious.

Fjordur's hardest cave is Nidisheim. This cave has a lot of traps such as spikes, arrows, and creatures. The entrance is underwater on the far western coast of Vardiland. After going through a short underwater tunnel, you will come upon an air pocket. You will want a TEK Chestpiece to go up the shaft because grappling hooks, even though they can be used outside of the final area, it is simply easier with a TEK Chestpiece, because you can actually get Element on Fjordur without having to kill bosses! Don't forget to mine the green gems up the shaft! After you go up the shaft, you will enter a large chamber where you will have to kill a bunch of enemies such as Desmodus and Megalania. Besides the creatures I mentioned, most of the creatures in this cave spawn up to 2x the server level cap, like most of Fjordur's caves. At the end of the room, there is an entrance into the dungeon part of the cave. You cannot use grappling hooks in the dungeon. You will have to go through the dungeon's many corridors and get the combinations to enter the next part of the dungeon. The first combination is: Green, Yellow, Purple, Blue. Make sure you press it in that order, otherwise a bunch of Araneo and Arthropluera will spawn on top of you! After that, you will come into the second half of the dungeon, where you will have the added threat of instant-death spikes in pits on the ground! There will still be combinations you will have to enter, though, and the combination for the second part of the dungeon is: Green, Purple, Yellow, Blue. After you enter in the combination, you can retrieve the Artifact of the Massive, needed for summoning the Broodmother Lysrix on Fjordur.