“ The Chinese, when attacking a castle or fort, flew kites over the city wall and used the length of string it took to get it there as a measurement to know how far they had to dig a tunnel to get under the wall.”
“ The PCs are accosted in a major city containing at least one famous fortuneteller / prophet of the future. They are informed that their as-yet-unborn child will (insert terrible evil), and that, although they are very sorry, the PC must be executed to keep this from happening.”
“ Perhaps the product of another universe or time, this vessel appears as an early Tall ship, but is made of iron from keel to spar. The sails are a battered canvas but are nearly indestructible, but in truth do little to move the ship - the ship is able to move even with no winds.
The ship is powered by life force, requiring regular sacrifices to ‘charge'. The victims are cast in front of the vessel as it moves, it's razor sharp bow bisecting them. The ship may initially be missing key components and the ritual to power it would also require research by would-be users.
The ship has no built in weapons aside from the bow, which can easily cut even large wooden ships in twain.”