The Gygaxian Gyre is a deep and vast place, and the Perrenian Necrohol is one of the zones of the dungeon that almost all explorers lucky enough to survive the Gyre proper are introduced to

In this walled compound, the demons Oni and Engel keep an avatar of the Lord of Black Pleasures DanXurin contained inside a magical barrier. It is best if you don't allow it to escape.

The Stalker Mausoleum is the hulk of a Stalker assault mech, converted into a mausoleum by a wasterlander warlord known as the Devastator 

The islets are all that remains of the Island of Yava

26/30 Sample Dead Zones to flesh out the wastelands of the Cosmic Era.

The ruined city of Oldport, destroyed nearly 200 years ago during a violent raid from the sea. During the day, a desolated skeleton of what once a thriving port city. During the night, magical splendor causes the city to regain its former glory and the dead rise to continue their lives.

The ruin that birthed a society; the Life and Times of a city in the throes of death.

'We came expecting a broken moon or wayward asteroids, but this... I don't think anyone's seen anything of its like. There's an astounding amount of material here. We're looking in the records, trying to match some of the artifacts, but there's nothing like it. I don't know what most of this does, but my God is it complex. We're looking at, at least, what, two decades of potential salvage, maybe more, then the cartography of the local moon for more. We're definitely here to stay.'

- Phaeton Venator, recovered personal log

Rumors of the closed city are whispered on the mouths of the other races, however no one will ever find a dwarf that will say one word about it.

What danger lurk within the ruined city streets?

'Reills. E'en the name makes me shudder. That there is unholy ground, cursed by most gods. Not even the demons and devils and the incarnations o' evil dare step foot there. Reills. You know me, I think money likes it in my pocket instead of wherever else it is. But, and I've heard rumors that say this, if theirs treasure on that ground, it ain't going in my pocket on pain o' death.'

-Old Gerald, man in the pub.

What lies under the turf deep in the earth of that grassy mound? The PCs would very much like to know...

Just off the craggy cliffs of Corundum, under the rippling blue ocean waves, seven stones stand. They rise majestically from the ocean floor, references to some long ago civilization. Meaningless, now, to all but the most learned.

Deep in the remote Storm Horns lies an ancient and deserted city of giants.

The empty shrines of a god so old, all but his name is forgotten.

11 great statues of lost gods being chipped away by the condemned.

Inspired some years ago for a Kult/CoC Halloween game

Knowledge is Power. That is, he who makes the knowledge, wields the power.

The Yughort were the fathers of the steppe civilizations, rulers of the first nomadic empire of the plains. Their signs can still be found, including their conical burial towers.

During certain years, people in Akgku claim to observe a green flame coming from the sea and erupting upward. It can be observed from a distance of two days' journey or more. After burning for a considerable time, the flame disappears.

—Falklyde Wodinger, Haraconian scholar, in route to wondrous Udross and legendary Akgku.