Tutorials/Defeating a monument

Ocean monuments are dangerous for unprepared players, as they have many dangers, including guardians, elder guardians, and many rooms that are easy to get lost in.

Reasons for defeating an ocean monument
There are a several benefits of defeating an ocean monument:
 * To get the 8 gold blocks in the core.
 * To obtain sponges, sea lanterns, and prismarine, which cannot be obtained any other way in Survival mode.
 * To set up a guardian farm, which allows you to get even more prismarine, sea lanterns, and fish.
 * For the experience you get when killing guardians.
 * For the challenge.

Dangers
The most common mob within the monument are guardians. They swim quickly, have health, and have two ways to damage the player:
 * A laser is their primary offensive attack. It takes several seconds to charge, emitting a distinctive sound and changing color from purple to yellow in the process, and does significant damage when the charging completes.
 * There is no way to dodge the laser, but the guardian must maintain line-of-sight during the charging process. If you can get behind a wall or pillar, the attack will be canceled and will do no damage. Circling narrow pillars therefore can be used to circumvent multiple attacks from all sides.
 * The laser has a maximum range of about 15 blocks. If you can get far enough away before the charging completes, the attack will be cancelled and do no damage.
 * If the player gets too close to the guardian, it is liable to abandon the attack and swim away.
 * Guardians also have a natural Thorns-like defense. If attacked while their orange spikes are extended, the attacker will take damage.

Each monument also contains three elder guardians. They have health and a somewhat stronger laser attack, but move slowly and infrequently. They will also inflict any player within 50 blocks with Mining Fatigue III for 5 minutes, checking for nearby players to afflict every 60 seconds. You will want to be sure to kill the elders in a manner that counts as a player kill so they will drop sponges. When an elder guardian inflicts you with Mining Fatigue III, then you could drink a bucket of milk. Even using an unenchanted diamond pickaxe to mine a single block of prismarine will be a true challenge when under the effect of Mining Fatigue III. However, drinking milk will also remove Water Breathing, and you will just get Mining Fatigue again. An easier way is to wait until you have defeated all 3 elder guardians before drinking milk. Until then, simply don't break blocks, and only travel through pre-made passages.

Locating an ocean monument
Ocean monuments are only found in deep ocean biomes, so you'll need to find an ocean and explore it. Being underwater, the monument may be difficult to see, but the sea lanterns are distinctive and are usually easily visible if you're looking for them. You can also listen for the sound of guardian lasers as they attack squid.


 * Using a boat is the easiest way of searching for a monument.
 * The sea lanterns on the exterior may be easier to see at night.
 * A potion of Night Vision helps to see the monument from above the water. The respiration enchantment greatly enhances vision while underwater.
 * If you have enough, ender pearls can help travel large stretches of water quickly.
 * Online tools, such as this one. can be used to locate monuments based on the world seed.
 * Using a resource pack with clear water textures makes it easier to see the monument.
 * Using an Ocean Explorer Map from the cartographer villager.
 * Using the command ( in Java edition).

Equipment checklist
Equipment that is particularly helpful when infiltrating a monument:
 * Diamond armor is helpful for its strong defense. If at all possible, obtain these enchantments:
 * Respiration III will enhance vision underwater and will allow you to spend less time worrying about your air supply.
 * Aqua Affinity speeds up mining blocks underwater.
 * Depth Strider III increases your movement speed underwater.
 * Protection will reduce damage from the guardians' lasers and thorns.
 * A strong weapon, such as a diamond sword or diamond axe, enchanted with Sharpness V. Bows aren't very useful underwater, but can be helpful if you're drying out the monument when guardians approach an already-dried area.
 * Food is essential, since you will be taking damage and will want to regenerate. The best options are steak or cooked porkchops, since they stack and restore each.
 * Slime blocks are very useful for walling off areas you don't want to go to (yet), creating barriers to break line-of-sight, and otherwise marking your path, since they can be broken instantly even while affected with Mining Fatigue III.
 * If you can't get enough slime blocks, you might also try snow (3 seconds to break with Aqua Affinity and an Efficiency V Silk Touch diamond shovel), mushroom blocks (3 seconds to break with Aqua Affinity and an Efficiency V Silk Touch diamond axe), or netherrack (6 seconds to break with Aqua Affinity and an Efficiency V diamond pickaxe). Or use doors, since they can be opened and closed.
 * Potions of Water Breathing (extended) allow you to ignore your air supply and concentrate on avoiding guardians and finding your way through the maze.
 * Potions of Invisibility (extended), while wearing only boots (for the Depth Strider III), can allow for sneaking past the guardians to hunt the elders or to take other resources. However, currently renders this strategy unusable.
 * Potions of Night Vision (extended) can help with seeing in dark areas of the monument.
 * Milk will remove the Mining Fatigue effect, allowing you to mine through the walls of the monument to reach your destination easier. However, do note that this will also negate your beneficial potion effects, and the elder guardians will re-apply Mining Fatigue within 60 seconds.
 * A bucket can be used to refill your air meter underwater, since using it will pick up the water block at your head, replacing it with air long enough for the player to get replenished with an air supply. Torches can be used for the same purpose. Doors, ladders, signs, and other partial blocks can give a more permanent air space underwater, but note that you won't be able to easily move them once placed.
 * If you're drying out the monument, ladders can also come in handy for getting up and down within the monument once the water is gone.
 * If you're planning to collect sea lanterns, a tool with Silk Touch will collect them whole.
 * If you're planning to try to mine through the walls while affected by Mining Fatigue, you'll probably want a diamond pickaxe with Efficiency V. And even then, it'll take 30 seconds per block.
 * If you do decide to dry out the monument, sponges are extremely useful for that purpose if you find some inside the monument. In that case, you'll also want a furnace and fuel to be able to (re)use them.

Defeating the monument
Before entering, make sure you have turned auto-jump off.

The first step is to get inside the monument, which can sometimes be difficult as guardians spawned outside the monument and will attack you. There are several ways you can get in:
 * Go in the front door. You might throw an ender pearl to get there quickly, dive from above (especially from a height), or run along the seafloor with Depth Strider III boots.
 * Mine through the roof above the elder guardians' rooms. It can help to build a quick bunker around the site, and use milk to counteract the Mining Fatigue.
 * Tunnel up from below. For this you'll almost certainly need milk to counteract the Mining Fatigue.
 * If the player creates a platform over the apex of the ocean monument, TNTs can be activated and dropped down and an elder guardian can be killed without any structural damage. Also, if structural damage is preferred, sand or gravel can be dropped after the activated TNT, which will make the TNT explode inside the sand block, and structural damage will be dealt. This method can be repeated over the left and right wing of the ocean monument, to kill the rest of the elder guardians. This can also be done underwater, by placing a sand/gravel block on top of the placed TNT, and activating it.

Once inside, it can be advantageous to set up a base of operations. Doors or slime blocks can be used to seal any entrances to the chosen room, and slime blocks can be used to quickly clear it of water. Then you might move in resources such as furnaces (for drying sponges), chests (to hold potions and other supplies), a bed (in case you die, you'll respawn closer to your dropped items), a nether portal (for easier access via the Nether), and even a cow (for milk refills).

Your goal inside the monument is to take out the elder guardians to eliminate the Mining Fatigue III that hinders your ability to obtain the resources from the monument. There are three per monument: one in the "penthouse" at the very top and one in each of the wings flanking the main entrance. The elders themselves are not extremely difficult if you're prepared with strong armor and weapons, since they move and attack relatively slowly, but finding them within the maze can pose a challenge. It might help to wall off dead ends as you investigate them, and note that the wings are connected by a long hallway around the back of the monument that bypasses the maze.

After the elders are defeated, you might simply take the sea lanterns, sponges, prismarine, and gold and leave. Or you might remove the water from the monument ("dry it out") to turn it into a base or a guardian farm. Now that Mining Fatigue is no longer an issue, you can use any method you'd like to accomplish this; if you were lucky enough to find a sponge room, the sponges will be particularly helpful in this task, as the sponges will soak up a lot of the water.
 * Even if you did not find a sponge room, you can use the sponges from the elder guardians.
 * If you have been to other ocean monuments, you can use previously-obtained sponges.