Huge Ruined Piles I (Random Table/Any System)

From Gormenghast's vast ancestral mansion to the Final Redoubt in the Night Land, there's nothing quite so quintessentially old school as a Huge Ruined Pile and the Megadungeon that awaits below.

From Dungeons and Dragons, Volume One: Men & Magic, page 6:
"...the participants can then be allowed to make their first descent into the dungeons beneath the 'huge ruined pile, a vast castle built by generations of mad wizards and insane geniuses.'"

Huge Ruined Piles tend to be scattered all about the place, alongside various and sundry Cyclopean Ruins, Abandoned Settlements, Isolated Freeholds, Fortified Baronies, and the like. But for now we're only interested in the Huge Ruined Piles that might just be cropping-up here and there...

Huge Ruined Piles: Table I  (D12)

1. A heavily overgrown fortress that has had most of its major walls toppled and ruined by a siege that ended hundreds of years ago, yet in places the fires still smolder and grim shadows still linger.
2. A huge, vine enshrouded limestone sinkhole that was once carved into a massive palatial space filled with incredibly bright and colorful statues and idols, now flooded and coated in thick masses of algae and stinging weeds.
3. A series of Seven Ziggurats arranged in a straight line, each one constructed so as to capture and focus the energies of a particular nexus or cluster of Ley Lines.
4. Four massive, steeply-sloped basalt Pyramids built at the corners of a shared quadrangle that is now a lush forest growing up the sides of each the Pyramids. There is a small artificial lake hidden beneath the dense canopy of the forest. At the center of the lake is an island.
5. A mile-wide dome of translucent material, completely not like glass, shattered and broken, with shards ranging in size from a thousand feet long to fine grit and everything in-between sits forlorn and forgotten within an eerily silent box canyon where nothing grows amidst the tainted violet sands.
6. A dead city built from massive blocks of some waxy, reddish stone. All the roofs have collapsed and the streets are now filled with slender pale green trees that grow extremely tall before unfurling their umbrella-like foliage. Squat, bulbous cycads like curdled masses of tan and beige warts have worked their way up from beneath the ancient cobbles to fill the cool green spaces beneath the trees with a gently swaying sea of ferns.
7. The walls are crumbling almost as fast as the metal supports are eroding, all of it crashing down into dust, rust and debris. At the center of this place a flickering blackness dances and contorts like some mad ballerina made up of smoke that can only really be seen at night.
8. A single tower of rough stone, barely three stories tall. The outer surfaces are darkened and slick with a strange greenish glass, as though the very walls were exposed to some incredible source of heat that nearly melted the place long, long ago.
9. Obsidian splinters form nasty, lacerating walls across the gullies and rutted defiles of several inter-connected valleys that have all had a canal cut directly into the bare rock. The canals all lead back to a single grand reservoir surrounded by massive splinter-walls to which no vine or creeper can cling.
10. An ancient sacred city built with special shrines, towers, observatories and temples spaced around the circumference of a circle. The motions of the stars and planets are tracked and celebrated by the various alignments of the old structures. But it is abandoned now. Only a few crude ape-things or the large green and blue birds that prey upon them ever go there any more.
11. A six-mile across hexagonal island of dark green stone rises from out of the incredibly salty dead lake. Nothing grows upon the six-sided island for most of the first mile inland, then it suddenly erupts into feverish greenery and gurgling vegetation that moves with rhythms and impulses that have nothing to do with the wind.
12. Heavy metal walls more than a thousand feet thick jut from the rocky slopes of a curiously truncated mountain. Pitted and scored with the marks of ancient weapons and a terrible war from prehistory, this place is what is left of a great aerial fortress that was brought crashing down in the final days of a war that even the gods have forgotten.

To Be Continued...