My own fortress, now the grand city of Crypttests, has received a lot of help from the community to get where it is today!
The expedition team was dispatched in the year 200 to found Crypttests near the tower of a nefarious necromancer. It seemed a doomed expedition with the undead right over the horizon, but the wise elder Amost was determined to see her team to success. She decided that the best defense against the undead, in light of the fact that they had but one skilled warrior, was to dig downward until they'd located natural caverns. The bounty provided there would bolster the growth of the city, and they could make the descent far more difficult for the necromancer's forces.
Crypttests began as a very small settlement dug into a valley on the lowest levels of the caverns, with the areas just outside utilized for grazing and farming. You see, not only had they brought cattle, but also four mighty war unicorns. The culture from which the people of Crypttests hailed believed them to be sacred beasts perfectly suited to fighting undead. They would fend off many minor menaces of the caverns, but become much more important later.
The early years were difficult times for Crypttests. Each time they would seal off a route for cavernous threats to reach their small home, the beasts would find another. Several seasons of crops were lost to ogres and trolls who rampaged across the fields before dying at the settlement's outer walls. It was thanks only to an abundance of natural resources - namely gold and edible plants in the caverns - that the dwarves survived the first two years. A human caravan would come early in the year to bring a bounty of food, and another from the Mountainhome just before the winter. If the people of Crypttests traded poorly, then shortages between had to be resolved by picking as much of the caverns' natural bounty as was possible. Sweet pods became a staple food of the town.
Slowly but surely, Crypttests ascended in security and sustainability, as well as size. What was once a mere hole in the wall now had an entire city on its first level, the Old City, and a more lavish second level for the growing population of nobles and officials - as well as a need for added space to house the locals! Indeed, Crypttests had fast accumulated all of the dwarves it could handle, as well as countless performers and scholars from far and wide. Humans, elves, and even a goblin or two chose to settle there permanently.
The first mayoral election saw Amost removed from command as expedition leader and replaced by Olin, an old fisherdwarf who had done nothing (there weren't even any lakes to fish in!), possibly due to a stock of human booze. However, this would not stand for long. The next dwarven caravan in the year 202 would deliver news that Crypttests was to become a barony, and the people overwhelmingly voted old Amost to the position! Olin remained mayor, but elderly Amost could now hold her newfound clout over him to the end of her days.
As time went on, the dwarves of Crypttest fell under siege twice by the undead of their enemy, but both invasions failed due to the cleverness Amost had passed on to the local dwarves. They had slowly but surely reshaped the caverns to suit their needs. Unnecessary paths down to the fortress valley were struck from the cavern, while great walls and fortifications of marble were erected to block off other routes of entry. Measures were taken even to the very entrance of the city, where two walls now stood, both with mighty drawbridges ready to entomb the dwarves and their animals in the event of a serious threat. Also, they invented garbage disposal and send their refuse via minecart to a lava pool far below. No longer were their pastures plagued by the miasma of the dead.
By the year 202, threats from the fortress' necromantic nemesis had all but fallen silent. Many wondered if something had happened at the tower to end the threat, thus freeing Crypttests from its duty to stand guard against the unholy powers. That isn't to say that the fortress was safe, however! Ordinary cavern pests aside, many forgotten beasts sought to conquer the subterranean city. One of the earliest was a gigantic bird whose wings bypassed all of Crypttests' defenses. The beast was stuck down by Catten, the very same lone warrior who had arrived with the expedition party and had long since been made militia commander.
Other forgotten beasts would come in due time. One merely passed through prior to Crypttests having reshaped the caves through carving and walls, but it may have had the greatest impact. A plan to turn the massive mold fields just above the valley into bountiful farmland was long delayed by the arrival of a mysterious red blob whose jiggly form set the plain ablaze. By the time the beast had passed through, the fire had burned out of control and left only ash behind. It would take quite some time for the mold to grow back and the farming plan to resume.
Other forgotten beasts were stymied by Crypttests' engineering wonders, for the most part, but one last beast did reach the gates in midwinter of 202. Ngogno Deadholes, the Fates Shadow of Mines, had actually been on a rampage through the caverns for some time. How he finally bypassed the city's outer defenses is unknown. However, doing credit to their reputation as holy beasts, Ngogno's reign of terror was ended via a killing blow dealt by the unicorn Conjurebrass.
The accomplishments of the great metropolis of Crypttests could no longer go ignored. In early 203, without ever appointing any nobles beyond the baroness Amost, King Iden Zanzegim and Queen Kib Dorennish relocated to the city and declared it to be the new Mountainhome. They did not bring any of their fourteen children along. A third level was constructed, a grand palace to house the royalty and serve as a central complex for the city's politicians. So begins a new era for Crypttests, a wealthy city facing few threats. The people now approach real danger for the first time as their new monarchs, hungry for the wealth known to be in the local earth, have commanded a hunt for adamantite.
The surface world was a worse place still. Wars had been constant across the three years since Crypttests' founding, mostly among goblins and neighboring civilizations. However, three demon lords seem to have been on the warpath, the eldest being the Cloud of Chaos. It has weathered colossi, dragons, hydra, rocs, and titans since perhaps before the year 200 and has still managed many conquests. Will their armies one day come to Crypttests, or will the dwarves welcome the demons in first via their quest for adamantite?
Last but certainly not least, the final forgotten beast seen by the locals had been slaying everything in the caverns for years, blocked off only by the mighty walls of Crypttests. It was finally slain, not by dwarf, nor man, nor elf, nor even goblin. This terrible forgotten beast was suffocated ... by a crundle. Crypttests, which had once considered crundles to be a frequent pest, now has a gold statue cast in their honor.