Okay, I've had a chance to do some experimenting.

@Don Anderson Jr. -- here's a test putting things on the SYMBOLS WALLS MARINE sheet. #A is from the Weeds symbols, #B is Seagrass, C is coral, D is the Wall Weeds, and E is Weedy Rocks. What do people think? Any favorite combinations here?

@Wyvern -- I experimented with creating a murkiness by adding the ADJUST HUE/SATURATION effect to the DEEP WATER sheet (which I moved above the walls so that the walls would block it), and then lowering the Hue and increasing the Brightness. I then used the "Water, default, deepest" for the areas closest to the Sea Hag and the "Water, default, deeper" for the murky water farther away.

Honestly turned out better than I expected. I created a DEEP WATER 2 sheet so that I could have different settings for the Deeper and Deepest water. Doing it this way allows me to keep the rest of the ocean untainted. Now I have to decide how pervasive the murkiness is. I could make the entire head area the murkiest, with the less murky fill permeating the rest of the lair, or maybe most of the rest of the lair. Or I could keep the murkiness just in the head area.

I will also add some bones and other debris, though probably won't add too much clutter.

Very Cool! I will experiment with vegetation and maybe saturation/brightness, or maybe shadows, though I want to make sure I don’t lose the beauty of the Marine Dungeons.

I'd like to be

Under the sea...

Here is the second of the three Marine Dungeons I've planned. The first was the Sea Elves Outpost, and the third will be a full-scale, multi-story underwater fortress (though it may take me a bit to get to it, as I'm letting myself get sidetracked).

My goal with this one was to go for speed. I wanted to see if I could create a nice dungeon in a reasonably quick amount of time. Like, imagine it's a Friday evening and I have to whip something together for my players who will be coming over Saturday morning.

I have a collection of public domain images produced by the Society for Creative Anachronism for use as heraldry symbols, and I used one of an octopus to use as a tracing guide. All told, it took me about four hours, I think, to do the first draft. I then went back to rip out the gardens that require sunlight (per the conversation in the Sea Elves Outpost thread) and replace with things that wouldn't require sunlight.

This one is called The Octopus' Garden. It's unknown who first excavated this realm beneath a marine mountain, carving it out in the shape of an octopus, but it has now become the lair of a Sea Hag.

Here it is unlabeled:

Here it is with labels:

The octopus' eight arms serve as wings in the lair (or maybe we should say tentacles instead of wings), with the suckers becoming small rooms in the lair. The southernmost tentacles open to the sea, becoming entrances to the lair, while the other six are fully enclosed. The chambers in tentacles 1, 2, 3, and 4 are used to produce food for the lair's residents.

As you enter -- if you can get past the sharks that the Sea Hag has enchanted to guard her entrance -- you'll see that the chambers closest to the entrance get just enough sunlight (improbably) to grow vegetation. The other chambers grow things that don't need sunlight, particularly marine mushrooms. (True story: freshwater aquatic mushrooms were discovered about 15 years ago. They're only found in a single mile-long stretch of the Rogue River in Oregon, in a spot where my family has a cabin that has been in the family for generations. But in my fantasy realm, saltwater mushrooms are abundant.)

Other chambers are used to raise shellfish, sea urchins, and anemones, who are all fed with vegetation harvested from the kelp forest outside of the lair on the northeastern side.

The chambers in tentacles 5 and 6 are all prison cells. If you look closely, you'll see a double set of gates in the entrances to those chambers. They all have hammocks for the prisoners to sleep in, but they are also all equipped with shackles bolted to the lair's walls for situations where a prisoner may need extra restraints. If you look closely, you'll see that two of the cells have humanoid creatures (probably sea elves) shackled to the walls. Another has a humanoid skeleton, while a fourth has the skeletal remains of some other creature. A fifth has an imprisoned mermaid, and the others in this closeup are unoccupied.

The chambers in tentacles 7 and 8 are are bedchambers, each equipped with a hammock and one or more chests so the resident's valuables don't go floating away.

The "head" of the octopus is a Great Hall, where the Sea Hag holds court. Today she has chosen to take the form of a giant octopus.

The two spots labeled #10, where the octopus' eyes would be, are extraplanar portals. Some say that one goes to a dangerous swamp in the Feywild while the other goes to an even more dangerous fen in the Shadowfell. Others say they go to the Elemental Plane of Water, or to soggy planes of the Abyss.

Why would our adventurers go there? Perhaps they are trying to rescue the mermaid, or the other NPCs. Perhaps they need to use the portals to get to the next stop of their missions. Perhaps they need to negotiate with the Sea Hag for help with something. (Maybe one wants to trade her voice for a love potion -- no, not that.) Maybe the Sea Hag has a magical artifact that they need to complete their quest....

Okay, I made some adjustments based on everyone's feedback. I added some kelp forests outside, and I added some hydrothermal vents/chimneys in a few spots (the garden as well as a few other "dead ends" in the entrance passageways. I put one in the room with the coral. Although coral does not photosynthesize and does not need sunlight, it does consume algae that relies on sunlight for photosynthesis. I am going to suggest that the coral here are able to survive on the microbes that thrive on the vents.

(Maybe some underwater creatures use the vents to cook their food, too?)

We'll still have to assume that luminescent crystals provide ordinary lighting in common areas, and some sort of magical sunlight appears periodically, enough to provide photosynthesis for the foliage in the cavern areas (I decided not to remove them).

I'm making some tweaks to my next marine dungeon based on this as well. But first, here are some images showing the changes to the Sea Elf Outpost.

Some potential adventure hooks off the top of my head:

1. The adventurers were taken captive after stumbling across the outpost.
2. The adventurers were sent to negotiate for the release of an NPC ally who was taken captive.
3. Sahuagin raiders have overrun the outpost, and all of the sea elves who knew the location and magical coordinates of the teleportation portal have been slain or taken captive. The adventures have been tasked with sneaking into the outpost to find the portal and learn the coordinates so that a proper rescue party can teleport in to take the sahuagin by surprise.

Happy June! Happy start to the meteorological summer! We're having a little heat wave in Northern California (80 F / 27 C here in San Francisco, but more like 100 F / 38 C just a few miles inland). So it sounds like a perfect time for the beach.

I haven't posted new maps in a few weeks because I was busy working on a few big ones. Right now I'm working on the interiors for the ziggurat I created to play with the new stairs annual. But while I was working on the lighthouse (more more experimentation with stairs), I got the idea of doing a proper fully underwater adventure. Something that the adventurers would need a Water Breathing spell or similar magic or innate ability for.

I have three ideas. One is an underwater lair of a sea witch or sea hag. That's ready to be posted next. Another is a fully underwater fortress or castle. I haven't started that one yet. But for this one, I wanted to do a Sea Elf Outpost that's a combination of caves v. construction, and underwater v. above. This Sea Elf Outpost is probably my favorite map of all of the ones I've created. It uses Marine Dungeons as the base, with fills and foliage symbols from Forest Trails and furniture from DD3.

In my campaign world, sea elves are reclusive and distrustful of the surface world. When they have to go about on land, they disguise themselves as high elves, so most "landlubbers" don't even know they exist. At this outpost, the sea elves can secretly spy on a nearby human city and the movements of the human Lord Admiral's navy.

Here's the island from above as the crow flies -- or in this case, as the seagull flies.

To give you a sense of perspective, this map is 1000 x 800 feet, and the hillside along the beach stretches about 625 feet. On the images with a grid, each square is five feet.

Seems uninhabited. But if we could use x-ray vision to see below the hill, this is what we'd see:

Come on in! Let me give you a proper tour. First, let's start with the main entrance (#1) and the first guard post (#2).

These underwater passageways eventually lead us to the Welcome Chamber (#3), sort of an underwater reception room. To the south is the underwater gardens (#4) where the sea elves grow various sea grasses, seaweeds, and marine mushrooms. To the east is the Great Hall (#5), with a storage room (#6) to the north. To the south, there are two locked rooms: the armory (#7) with spears, tridents, nets, and other weapons suitable for underwater combat, and the treasury (#8).

Next on our tour, we find three VIP bedrooms (#9) as well as group barracks (#10) and a storage room (#11). Of course, ordinary beds would be useless in an underwater bedroom. Who wants soggy sheets? I figured they'd probably use hammocks that they can tie themselves into so they don't drift away in their sleep (like astronauts in zero gravity). The hammocks connect to a wall on one side and a pillar on the other.

Next up, we have a room that has been nicknamed the Transition Room (#12), as it transitions from underwater to surface land. It's one of three rooms with ceilings high enough that the water doesn't touch the ceiling here, so you can pop your head above water even in the marine parts of the room. To the north is a room (#13) where folks can dry off and change their clothing, though the sea elves generally wear lightweight linen clothing that dries quickly on their own. Room #14 is called the Lesser Hall. It's nicknamed the Map Room because it's where the outpost commander and his staff pour over maps and other documents, which couldn't really be done underwater (unless they used clay tablets or waxed paper, maybe). To the north is another storeroom (#15), and then there's a dining hall (#16), kitchen (#17), and pantry (#18).

South of the Transition Room, an underwater passageway takes you to the second of the three rooms where the water doesn't reach the high ceilings: the chapel (#16). This room gave me an excuse to play with the brass inlays that I love so much, as well as the partially-submerged pillars with the ripple effect, and the partially submerged stairs. The orange/pink tiled area is an elevated platform. Maybe I should put chairs or something on it to make it clearer that it's above water. In my campaign world, elves use henge stones as places of worship, usually with seven inner stones representing the seven gods of the elven pantheon. Here, the sea elves have used pillars as a substitute.

From the dry passageways that head north from the chapel or east and then south from the dining hall, we get to the above-water bedrooms. The outpost commander's room is #20, and then there are two double-occupancy VIP rooms (#21) and dry barracks with seven beds (#22). Room #23 is a recreation room where during downtime, the sea elves stationed here can play games or make music (there's a harp on the table).

Next we come to the third room where the water doesn't touch the ceiling, my favorite room of the outpost, called the Dolphin Room (#25). Here, a separate passageway to the outside allows for intelligent marine allies to visit and confer with the sea elves: merfolk, intelligent dolphins, and an intelligent octopus. (Not sure if the turtles are also intelligent or if they just wandered in.) A platform on the west side is elevated above the water, where there's a chest with balls, hoops, and other lightweight, floating toys that the elves and dolphins use in various games they've devised. A dry passageway takes you to the lockup (#26), where unwary landlubbers who've stumbled across the elves may be held.

To the east, the Great Staircase (#27) takes you winding up to the top of the hill, where elves are posted as lookouts. On the way, you'll pass a locked room (#28) with a teleportation portal and an open room (#29) where the sea elves stash their bows and arrows and other land weapons.

A spiral staircase (#30) leads to the outside above the top of the hill overlooking the beach. (You can barely make out the top of the stairs above the #30 label.)

And one last feature on the island: the Alligator Cove (#31). The alligators are enough to deter casual visitors from the island, and the sea elves do enough secret mischief to more determined visitors to convince locals that the island is haunted. (The alligator symbols are actually crocodiles, but I got the names mixed up. They come from Dundjinni Archives.)

And that's the end of our tour of the Sea Elf Outpost! It took me a few weeks, which is why I haven't had a chance to post anything new recently.