The legend says there was a treasure and there was a map showing the way. The map was engraved on a stone tablet. But the tablet was broken into hundred pieces by an angry warrior who could not understand what it says. People say parts of that map can be found while digging the ground or looking into animal hideouts. But other people say it's just a common stone, called striped flint.
Make a map, maybe up to 3 maps showing actual locations in the world, transform these to lineart style resembling striped flint pattern. Slice the map into 100 pieces each, possibly shaped like puzzle pieces, or stone age approximation of puzzle piece shape.
The map pieces can be found doing various activities with fixed percentage pool assigned to each activity, so:
- 5 pieces of each map goes to global trash pool
- 5 pieces of each map can be found while fishing, possibly same as global trash pool,
- 5 pieces goes to each type of dungeon (that's 3x5 at this point), would be nice if there was more types of dungeons, There is only small chance to find a map piece in any particular dungeon.
- 5 pieces can be dropped from trolls or possibly other high level mobs
- 5 pieces can be found while mining
- 5 pieces can be found while drawing water from a well
- 5 pieces can be found while collecting clay,
- 5 pieces can be found while chipping stone,
- 5 pieces can be received from quest givers,
- optionally 5 pieces from underground quest givers only,
and so on.
Other possible activities: soil digging, butchering chicken, moles, digging a grave, raiding ant hill, digging a cellar, demolishing a structure, etc
The activities have to be chosen in such a way that each sort of Haven players receives some of these. Majority must be available for even newbs to find while small number must be accessible only for well organized large groups. The idea is to ensure the hunt for flint shards is a tedious task, taking a lot of player interaction.
All those events can also yield a random piece of flint that can not be used as a part of a map but can not be distinguished from a real map piece other by trying to fit it with other pieces. There should be at least another hundred unique flint shards. That could be actually another picture, not related to maps.
Piece of map which is destroyed (dropped, used as a regular stone) returns to the pool to be found later again. The chance of finding is adaptative to the number of pieces already found so pieces are found at even rate over period of one year, so a pool which is badly behind the schedule will be elevated to 100% chance of dropping a map piece.
Optionally: pieces of maps can be stored in the village idol and can be removed only if the idol is destroyed. (Yeah, I am shamelessly stealing this part from other ideas

After the map is completed it can be taken off from the idol and used. It would show a minimap of an actual region in Haven, in the state how it looked at the beginning of the world. The map can be also traced like a scent, amount of charges is disputable, but I see no problem with infinite charges. The map can be used on the exact tile it points to, yielding an unique gear piece, like a cape.