I swear my fortress is cursed or something and is some kind of fun repellant.
Although I have a population of more than 160 citizens and more than 80k exported wealth, I've yet to get a single megabeast attack, a siege or even some minor harassment from nearby hostile civs.
The first forgotten beast that showed up was a giant quail with lidless eyes. It didn't even manage to get into my fort - it fought some draugr marksmen down in the first cavern layer, managing to kill them off, before wandering off into the unexplored areas. Later I found out it was killed by a regular geist - how exactly, I have no idea. I dont know where the geist is either - my dwarves made statues of the encounter, but I couldn't find the named geist anywhere - I don't know if he/she is dead or anything.
Next up, the thing that is happening currently - merchants from my civ came, but no trading took place - why? They were unpacking for the entire duration of their stay. I have no idea why.
Lastly, another FB came around, this one from the bottom-most cavern layer. It fought some magma crabs, which did what they usually do and spat magma at it. It managed to kill them off before it burned to death.
I have two adamantine spires that I could dig out and possibly unleash the circus.
On the other hand...I had this idea in my head of digging them out when a siege comes over. I'd have my military stall whatever race decides to try and get me, have some miners dig out the spires, then barricade some survivors in a safehouse that I dug out underground, only letting them out after the carnage is over.