Made this decently sized stone fort, took a lot longer than it should've, since I did about 80% of it without cheats. The stone cost alone was over 10,000 stones and I didn't want to spend the additional 20 hours I would've needed to get the last stones I needed.

THE YOUTUBE VIDEO HAS A DETAILED SHOWCASE WITH TIMESTAMPS!

The fort features:

Five towers with two very different versions
  Ramparts along stone wall and each of the towers
A Grand hall with a lot of space (and mead)
  Under the grand hall there is a secret vault
  Secret trap when facing the throne (just before the steps) all victims of trap will die, no getting out of it without help.
A kitchen/brewery
A functioning port with two ships
A house to call home
  Second level includes storage and balcony
Two jail cells with a bed and a bucket to excrete in
A fully upgraded forge/workshop area
One portal which transports you to a mysterious portal room
A windmill on the mountain
Two bridges to the fort on opposite sides

The fort is between a mountain and the ocean with water separating the front and back entrances, I think it would be fun if you were to download this world and remove all the items from the storage area and start a new adventure :)

It does feel like the fort itself is missing something in the center, I think a tourney arena would be great there.