Woodland Mansion

"What are the Illagers doing in that dark, secluded mansion of theirs? With its Redstone jails, elaborate altars and hidden rooms housing strange obsidian structures - it really seems like they are plotting something."

- Marsh Davies

It is an very good beginning for other great builds. It’s also the base of the Mineconstruct building.

Woodland mansions are massive systematically-generated structures found only in Dark Forests and their Hill variants. They are inhabited by evokers and vindicators, and one of the few occasions whereby a Totem of Undying can be obtained.

Generation
Woodland mansions typically generate extremely far from the spawn point, often appearing tens of thousands of blocks away. They can be located with woodland explorer maps, which are obtained from cartographer villagers, but they may not always point to the nearest one. Woodland mansions may also be tracked down with the command enabled by cheats. A Dark Forest biome with a woodland mansion is even rarer than a Mushroom Fields biome.

Like most randomly generated structures, woodland mansions can be found more frequently in a world using the Large Biomes world type.

Structure
Although their exact structure varies, all woodland mansions have some things in common: they all have 3 floors, with a wide variety of rooms, and generate a cobblestone foundation underneath the entire structure. The top floor is around half the size of the lower floors, and they all contain a large foyer that leads to a winding maze of corridors.

Rooms
Any given woodland mansion contains many types of rooms, but since the layout is randomly generated, some room types may not be present. Furthermore, certain rooms within the mansion are not readily accessible - some may have sealed entrances, while secret rooms have no entrances at all.

One may access the individual structures of a woodland mansion by using structure blocks to manually load room structures from the  folder in minecraft.jar. To do so, set a structure block to Load mode, enter, and press LOAD. A list of possible rooms, the names of these structures, and small descriptions are provided in the table below. Note that the room names are conjectural.