Over 40 years we've torn through a long list of adventures. Although the campaigns were often city-focused urbal crawls, there were a ton of dungeons. These are a few of the largest and most ambitious.
There's also a teaser sidebar with A Few Spots of Adventure in the Field Guide to the Lowlands (gated).
Dacartha: the Dead City
The capital of the Empire of Destin, lost behind its walls when it sealed itself from the world during the blood plague that followed the cataclysm of the Worldswell.
The Tower of Storms stands like an empty sentinel over the haunted remains of the great metropolis, the wealth of the world's greatest trading empire waiting for the brave and fearless.
Catacombs of the Hanging Palace
This is my answer to Gygax and his never-finished 100 level dungeon under Castle Greyhawk (and post-TSR as Castle Zagyg), or my own fever-dream version of the Halls of Arden Vul.
Tombs stacked on tombs stacked on temples to forgotten gods, below the crypts, sewers, and secrets of the ancient city of Akansha and the Hanging Palace of the Eternal Queen.
Temple of the Devourer God
Deep in the dry eroded emptiness of the Boarlands is the ancient temple to a lost god. Is it the Great Mother, whose call brings her skyvern children home? A facet of Relg Vyrkrin, the god of suffering? Insatiable tendrils reaching up from the dream-dark cosmos, ravenous, longing to be reborn and rise again.
The Ruins of Darkfold
The abandoned halls of Kaladvain, glorious city of the House of Fain, full of wonder, wealth, magic, and the secrets of the ancient world. It stretched under the spine of the Weatherpeaks from the Lowlands of Ebizhan to the Sinland Forest.
Many things went wrong when the city collapsed in -2030n, leaving behind a half-flooded ruin of broken halls, ancient horrors, most of it in a constant war between the orc tribes who now call it home.
A massive dungeon slog through the city, mines, and caverns of what was originally a version of Tolkien's Moria from Iron Crown's Middle Earth Role Playing.
The Black Cairn
Hidden in the high reaches of the Weatherpeaks, the Black Cairn is a maze of passages and magic that may even lead to another world. A classic dungeon crawl.
Isle of Seven Deaths
The burial place of Piris DeVir -- the greatest pirate to ever live -- and all his loot. Hidden in the West Isles of the Valek Sea, an entire island built to kill off the most seasoned adventurers.
Beldigard's Tomb
The legends of a magical tomb of the great mage Beldigard have floated through the centuries with scraps and hints that tease the location.
Based on the infamous "384th Incarnation of Bigby's Tomb" from Polyhedron, the RPGA magazine from ~1984, you can grab the pdf here.
Only one party in all the long years of Telrhin ever found it, and they left to regroup after a disastrous start.
Adoneda: the Temple of Gold
Legends of a temple of Safan, the Elephant God, lost in the jungles of Akanhara: stories of an elephant-sized idol made of solid gold, with diamonds for eyes, from the era of the Twin Thrones, a time of wealth and opulence.
Any adventurer traveling north of Akansha will be offered maps, guides, and secrets to the temple, an entire industry around a place that may not even exist.
The Lost Pyramid of the Hekasa
Somewhere in the sands of Arakhet, the pyramid of the Lost Queen was pulled into the sands never to be seen again.
With echoes of the mythic city of Qutb and the stories of its vanished civilization, the Lost Pyramid holds the secrets to a world still rich with the Great Dream.
The Buried City of Aervinel
Some versions of the myth say it floated in the clouds, crashing to earth in a catastrophic fall. It may have been a city caught in the schism of the Great Dream at its end. But all versions point to a ruined city of wealth and magic buried beneath the mountains.
I suppose this is the Telrhin equivalent of the AD&D GDQ Queen of the Spiders series: a continuation of Darkfold, and then after Aervinel would be the (barely sketched out) Throne of Talanasron adventures.
The Valley of Ash Agad
Hidden in a long history of betrayal, treason, and a vengeful king, the tombs and lost city of Ash Agad in the mountain kingdom of Rhask-Edaan.
This could be an entire campaign in itself, unearthing dark secrets and an ancient curse along with wealth, power, and adventuring glory.
The Elephant Tower
Looming over the city of Dryer Mob for centuries, the ancient temple to Safan became a hive of dark cultists.
When we ran it in 1985 it was a ten level dungeon you entered from the top of the tower. Full of magical rooms and puzzles, and home to the hegemonic order of the Red Priests.
Temple of Whispers
Okay so not a mega-dungeon, but the story is spread over three dungeons in the foothills of the Weatherpeaks: druid cults full of secrets, and an ancient world-ending beast that's starting to wake.
The third part, The Spider Cliffs, is a multi-level old school homage to Jennell Jaquays dungeon-building brilliance.
Dream of the Crystal Cave
At the edge of civilization, past the Desert of Quartz and the Lake of the Starless Sky, is the Crystal Cave.
Referenced in the Asahknor Fragments and the Gahl Bokat, mystical and labyrinthine caverns that touch the dream worlds of Oneiros.
TSR and More
We torched through a ton of AD&D modules in the early days: Tsojcanth, Tomb of Horrors, White Plume Mountain, Saltmarsh series, most of the A series (later bundled as Scourge of the Slave Lords), even the OG Ravenloft module.
The first time through Moria we used the Iron Crown Enterprises version for their Middle-Earth Role Playing game, which evolved into Telrhin's Darkfold.
Some Judges Guild stuff, Flying Buffalo, Mayfair, Palladium, some material from the world of Harn (Columbia Games), you name it.
All of these adventures were absorbed into Telrhin in one form or another. Even the Alice in Wonderland modules: Gygax wrote TWO modules based on Alice! Dungeonland and Land Beyond the Magic Mirror.
Somehow we never ran TSR's classic S3: Expedition to the Barrier Peaks, even though I've had that module since I was 13.
