While looking up fanfics that would quallify for a good mission I stumbled across one called Britannia Which is a 54 chapter suefic involving a country whose meant to be a child of Arthur(aph UK/England) while dating Alfred(Aph US/America) who got adopted by Arthur at one point and technically is her brother.

It's bad and when I get permission chances are this will end up being a multipart mission. However the thing that stood out to me was the castle that the sue has for her home. It's a castle which is completely ruby colored and apparently is made of either glass or a glass like material. Which somehow was kept hidden from her despite it taking years to build.
At first I misread it as a castle made entirely of rubies.

And I wonder,what other strange materials have gary stus,mary sues,and airy oohs used for buildings in fanfics? So,what kind of architectural nightmares have you all seen?