Do you remember the first time you finally pulled off a crazy project? What was it, and how many useless suckers poor dwarves died to build it?
I'll start:
I was inspired today by finally completing my very first magma smelter... Building the pump stack was a long and frustrating debacle, full of idiot masons walling themselves into corners. I had just begun building the watermill array to power the stack, and as I was channeling an access shaft to construct the power train, I accidentally designated an aquifer tile... Of course, one immediately adjacent to my central stairwell. The resulting flood claimed 4 dwarves, 2 cats, and shut down half my fortress... Luckily, I had quite a few haulers still on the surface, so I enabled mechanic, architect, and carpenter on all of them, built an emergency workshop, built a pair of pump components, and re-routed my power-train. Quite a bit of luck on this one, I had constructed my store-rooms towards the top of the fortress, so there were some rock blocks still laying about in an area that wasn't too flooded. Most of my fortress population was trapped down in my dining hall, about 6 z-levels below the storerooms... But that played out to my favor as well, because I had a pair of near legendary miners hanging around to dig a relief channel into the caverns. Without their heroic efforts, my emergency pumps never would have finished in time...
But, all in all, loses were primarily cats and useless migrants. I did lose one of my miners, which was a damn shame, and there is a horrid miasma cloud wafting up from the flooded cavern, but plugging the aquifer tile and finishing the rest of the construction was a snap! Now I have my very first magma smelter!