I decided to create a necropolis megaproject once. I made sure to embark on a location with plenty of obsidian, set up a very simple down-ramp on the surface to my underground entrance labyrinth-defenses-thing, and then next to it, built a large, more or less round footprint for a massive obsidian tower with gold columns (walls highlighting the obsidian; not actual supports). I built a dump-room for granite, attached masonries, locked a few dwarves inside, dumped them some food and drink and sealed them in. Permanent coffin-making slaves. The first of these was the first of those laid to rest in the necropolis; as it turns out, falling boulders of granite can have a negative impact on a dwarf's health.
Ten, twenty, then thirty floors. Tens, then hundreds of coffins. Obsidian doors were replaced with silver, were replaced with masterwork silver, were replaced with masterwork silver encrusted with imported rubies and black opal. I was extremely fortunate to get a handful of masterwork statues (of various sorts) of things like forgotten beasts; I draped them in jewels and enshrined them in the necropolis. And then I realized:
You can't have a mausoleum without bodies.
The slave-dwarves, having made a surplus of coffins, stopped getting food. This got me a few bodies. My standard military, by this point, were well equipped and seasoned veterans, suffering few (if any) losses. I enlisted anyone who wasn't legendary in some necessary skill, handed them a short sword, a buckler, and an iron shirt, and sent them onto the field. That provided a few more bodies. I culled the first-born child of every family with children, luring them over a pit with the promise of a shiny lever before pulling a drawbridge out from under them. More bodies. Any immigrants who weren't married and ready to start breeding went into the pit or the slave army. The game changed from one of survival to one of carefully monitoring the sanity of my breeding dwarves, judging who could stand to lose another child and when, isolating dwarves from each other to prevent them from forming relationships, and routinely rotating dwarves between burrows to prevent any relationships that did form from becoming friendships.
I think I had some seventy or so dwarves interred by the time I decided I was tired of the map, so I waited for an immigrant wave, isolated one dwarf in a room with plenty of food and drink, and locked the remainder in a 'processing room' with just enough spike traps to send the survivors into a berserk fury, melancholy, or madness.The final dwarf had the duty of wading through the gory mess, slowly dragging the bodies of the fortress's inhabitants to their graves; some elaborate tombs, others merely holes in the wall into which a coffin had been sequestered. And finally, when he was done, he was ordered to wall himself into a room at the top of the tower, at it's center; a room with only a single, empty, coffin.