A very large sprawling dwelling house.
In the Touhou series, one of Gensokyo's landmarks is the Scarlet Devil Mansion. This mansion is home to Remilia and Flandre, the Scarlet sisters. Other parts of the mansion include a Library called the Voile and is mostly inhabited by Patchouli Knowledge and the Clock Tower on the rooftop. The mansion's gate is guarded by Hong Meiling, as so that no one is allowed to enter the mansion (even though she allowed Marisa to enter by purpose).