The Pillar of Thunder: Three thundersteel girders support it, but they make no physical contact. Electrical arcs between them and the base of the tower somehow suspend it.

The Pillar of Thunder lies at the intersection of the material plane and the dream planes of smoke and mist. At the edge, natives of the material plane will still find it plausible that they remain in the material plane, but strange effects from the other two planes bleed in. Like you can walk on water. And darkvision doesn't work.

If you can ascend through the Pillar of Thunder's thousands of levels, you will reach the Elemental Plane of Air, which is the infinite space that spans between worlds. It's filled with air, and if you give a little kick off the top of the Pillar, you can escape gravity and float continuously through space, until air resistance drags you to a stop. You can swim quite inefficiently, but it's certainly better to have wings or some sort of craft.

You might be able to hatch an Elder Phoenix egg at the top of the pillar, or it might have to be a Thunder Phoenix egg. Not clear yet if it will work on Sun Phoenixes and Earth Phoenixes.

The City of <Unnamed> stands on a rock hovering magically hundreds of feet off the ground at the edge of the desert. It is the chief city of the aarakocra on the Burnt Coast. Catching the high fog off the Inner Sea, it has a marginally more lush climate than at sea level, though still recognizable as a semi-arid biome.

If one could pilot such an outcrop, it might provide a way to cross the Sand Sea and trade with the gold rich regions beyond. But the great machines mounted on immovable rods deep in its caverns haven't turned for centuries.

Quote from Jake4XIII >>

There could be a split. You could have a city that is overrun with evil. It all depends on the kind of lore you put behind things. Or you could build the lore on what you what bizarre feature you want the area to have. One I plan on using is a location known as Marching Wood. As it is a forest that rapidly expands and swallows towns into it. It is the home of the treants and they basically spread outwards, not to conquer but to spread nature. 

 I have a city where they build their homes into the treetops, like Lothlorien. But the trees also migrate to follow their herds.

I should emphasize that none of my players have even heard of these places yet. I wish my players would take greater interest in exploration. They seem to mostly be interested in money. I know - I'll tempt them to explore with riches.

Ziijdespin, the Cavern of The Drow is a massive underground cyst guarded by webbed gates made of pure mithril.  The city is painted in wild blacklight colors that fluoresce in ultraviolet light.  It's built on platforms and connected by a series of cable cars.  The overall effect is a lot like the city in Coco, except for what's dead in the center:  A huge balrog prince, his wings severed, bound by massive eldritch chains.  As it struggles madly against its bondage, its strength simultaneously runs dynamos that provide electric power through the city to power the cable cars, light and other utilities.  He has remained trapped there for over 500 years, like a fly in a web.  He has never ceased struggling but the residents of the city no longer even notice  him.  Few ever bothered learning his name; such is the banal cruelty of the drow.

I just created a coastal city that is protected by a stone wall, but most of the people of the city live in the wall, so the wall facing the ocean is riddled with balconies, and staircases to other locations in the wall.  There are houses and buildings below the wall too, but all the buildings are on stilts, as the ocean comes up almost to the wall itself at high tide, and during storms will reach the wall.   At high tide you can't walk the streets, but have to use the boardwalks and bridges, but at low tide you can walk under buildings and down the streets.  The buildings have zigzagging gangplanks, small boats tied up to staircases and porches, and swaying bridges between builds.  There are also the major docks for the trading ships to come and tie-up to.  I wanted it to feel like the people live in harmony with the ocean and not just fighting against it.  

Reminds me a bit of Gantzpoort in my world. A huge castle wall (the castle is actually just an immense man-made stone plateau a mile tall) surrounds an abandoned harbor. The harbor is no longer used since transportation shifted to airships. But it is "haunted" by reclusive kuo-toa.

Ooh, I like making interesting locations!

There are the Charwoods, which are cursed to remain burnt for all eternity, and contain all manner of horrible undead from the time when the forest burnt.

There is Rocswing Hollow, which is a great slabe of stone in the rough shape of a wing, propped up on another in the hollow of a hill to make a sheltered area, in which is a Fey Circle. In the feywild, the circle contains a wishing tree, where you can make wishes by tying a piece of ribbon with your wish written on it to the tree, and then buying a candle from the cave of candles to light and place on the tree. Payment can be left as valuables or sentimental items, or secrets and memories. If your offering is worthy of your wish, it may come true.

Picture of wish tree here!

The Wastes of Geltersid, the site of the gods’ greatest shame. Once occupied by wondrous cities and powerful nations, they delved into arcana that could undo the very nature of divinity. Angry because of the betrayal of their patron god, they declared war on the gods and their avatars. The gods won by basically magic-nuking the continent, causing most of the people to be killed. The magic-nuking reduced the once-beautiful landscape to little more than desert, stone wastes, and meager fields. It also had some long-lasting effects, including mutating some groups of snails to grow to ludicrous sizes and supernatural hazards throughout the continent. Only the mountains remain as far as geographical features.

Werehaven: A dark castle secluded deep in the wilds. A mostly abandoned village lies in ruins around the castle and has been overrun by the wild. In it, dwell the Beast and the Bird. They are the owners of the castle, and dwell in the secluded location at all times.

The Beast was once a kind and honorable prince who cared for his kingdom well who was attacked by a werecreature. He survived the encounter, but was inflicted with the curse of lycanthropy. He could not control the curse and would transform into a hideous monster and go on a rampage through his kingdom each night, attacking his own subjects. Knights came and tried to slay him, but they were no match for his animalistic fury, healers tried to rid him of his curse but their every attempt failed and would end with their death at his hands. Soon, his people deserted him, they fled for their own safety, and the abandoned prince locked himself in his castle to protect others from himself. He bound himself in chains, imprisoned himself in his own home, and the transformations became more and more frequent, to the point where only at one hour during mid-day was he freed from his hairy form. The curse somehow granted him longevity, drawing out his torture for over a hundred years. No one came near the ruins of his kingdom for his monstrous roars could be heard echoing through the mountainous landscape.

The Bird was a young girl, living in the small village of Raven"s Call. Once a year in Raven's Call, a Raven-haired woman would wander into town followed by a cloud of crows. She would walk straight to a single house and knock on the door. At that house, there was always a young newborn girl, and the Raven woman would claim that child as her own. This was considered the town's tax, and the townsfolk knew better than to refuse. If there was ever strong resistance, the next year would be plagued with disease and famine, and the surrounding wilderness would be especially harsh and dangerous, but as long as the child was willingly given to the Raven woman, the town would prosper, disease and famine would be unheard of, and the wilderness would be gentle. The girl was chosen by the Raven woman as her due, and they disappeared from town. She was taken up into the mountains to a dark, crow swarmed, stone tower in the middle of an ancient and shadowy wood. There in the tower, she was raised by the many Raven women who dwelt there. She learned that the Raven women bore a gift from the Morrigan. They were gifted with the ability to shift from the form of a woman, to the form of a raven and to also stop somewhere in between. In return for this gift, they must also serve the Morrigan, and perform who commands, whether dark or light, no matter what. They were her handmaidens and carried out her desires in the world. The girl was trained and raised by them, and was eventually gifted with her raven form, and became a wereraven. But when she was first sent out on a task, to poison the heart of a prince against the princess whom he loved. She refused. She was banished from the Raven women as a result, and cursed to always transform into her crow hybrid form as soon as the sun set, and whenever she made a transformation, it was no longer smooth and effortless, it was instead wracked with pain and anguish. She could not dwell among the humans, for they would fear her night form, so she was forced to travel along the outskirts of civilization.

As she was traveling, she came to the dark abandoned castle of the prince. It was growing late, so she sought shelter there and found a meal prepared at the table for her and a fire in the hearth. She ate and rested there, unaware of the horrific beast watching her from the shadows. When the sun began to set, she made her anguishing transformation into her monstrous crow form. The Beast was shocked and while he did not want the only human he had seen for years to disappear, he tried to tell her to leave, in order protect her from one of his fits of uncontrollable destruction. The Bird was frightened when she first saw him but overcame her fear and felt pity for the Beast. She refused to leave and stayed with the Beast in order to aid him and provide him with company. Over time, with the Bird's help, the Beast learned to better control his curse, but was still subject to the uncontrollable rages every night. The Beast and Bird married and lived in the castle together for a long time with only each other for company. Eventually, another lycanthrope wandered near their home, distancing himself from civilization to try to protect those he loved. The bird in her Raven form brought the Lycanthrope to the castle and gave him food and shelter. She helped him to overcome and live with his curse, and when he left, the word spread that there was a hidden home for the cursed where they might learn to control themselves and seek shelter. More broken and desperate people came to the castle, which came to be known as Werehaven, in order to free themselves from their curses, and many were aided by the Bird and the Beast. The place became a home for Lycanthropes and those who had no place to go back to, or would not be excepted back in their homes, would often stay and dwell either in the castle or in the old village outside it. Not all who come can be helped however, and some can become lost completely to the beast inside. Those who do roam the dense and wild forest surrounding the castle and village, making it a dangerous trip for those coming to the castle. The Lost will usually not harm the lycanthropes that live in the area because they are under the Bird and the Beasts protection. The Bird will often fly out to those who are coming to Werehaven and guide them safely to the castle where she will help them overcome their curse. Those that come to Werehaven receive shelter, safety, and training to learn how to better control their curse but some are completely lost to it, some learn to live with it, and some get to the point where only on nights of the full moon do they lose control.

The Beast rarely shows himself to those who come to his castle, and is most often in the form of a giant bear-like monster bound in chains who wanders the dark corridors of his castle in despair. The only thing that gives him happiness is the Bird who will often sing for him, and seeing how she helps those who take shelter in his home. If Werehaven or those who are hiding there are ever threatened, however, he will not hesitate to rush out in his great, snarling, beastial form and protect those under his care with his life. Those who have seen him in action are both terrified and in awe of his might and power but also touched by his deep anguish.

The Bird guides visitors to the castle safely and will help those who come to her for aid in learning to control the curse. She often takes the form of a beautiful, pale skinned woman with raven black hair with a kind gaze and a sorrowful yet graceful demeanor. She is skilled in the arcane arts and can skillfully cast many spells, as well as craft many magical potions and charms. She has a great store of knowledge from her time with Morrigan's Handmaidens and is willing to use her powers for good, but she will never leave the Beast for more than one night.

I created this place to provide a side adventure for my characters in case they ever contracted Lycanthropy of some form. In a campaign I am planning a character might become a Weredinosaur and so I thought I might need to find a way for my players to somewhat overcome their curse. The castle grounds will be expansive with lots of places to explore, like the library, the graveyard, the ballroom, the roof, the garden, and the village outside will be the home of various werefolk who are in different degrees of control of their curse. This is like a big mash-up of Beauty and the Beast, The Cloven from the Wingfeather Saga, and mythology.