A rather simple wonder (code wise), still I thought it was a cool effect:
The Lubyanka, a.k.a. the headquarters of the KGB, it basically functions as an 'evil' Taj Mahal where, once built, it will place all rival civs into anarchy. The length of anarchy is equal to half a golden age (so it scales with game speed). Spiritual leaders are immune to the effect (as are team mates / vassals). It also increases espionage throughout your empire by 20%
All the python is labeled and searching for "KGB" should find all the changes.
I recommend downloading winmerge to help combine the files. Includes a 3D wonder movie.
XML, python, wonder movie: me (tsentom1)
Edit: Added a line of code to take into account a rival civ being in a Golden Age.
Lubyanka (KGB) Wonder (XML+Python) 2016-10-05
Lubyanka (KGB) Wonder (XML+Python)