Woodland mansions are among the rarest structures in Minecraft, generating only in dark forest biomes and usually very far from spawn. The map finds them, which turns a multi-hour exploration trip into a known coordinate.

• Mansions are the only place to farm Totems of Undying from evokers — that is usually the real reason for the trip.
• The nearest mansion being 5,000+ blocks away is normal; a seed with one close to spawn is genuinely worth keeping.