Unique Improvements in Forests

Allow most unique improvements to be build in forests. You do not need to remove it first to build on. Appeal and Adjacency bonuses remain. Full list of allowed improvements below. Recent update added Patey and Hacienda from New Frontier Pass. I don't have the pass so I cannot test, please tell me if it does not work. I also changed the code so without any expansion you can still use it. Fort City Park Chateau Colossal Head Great Wall Kurgan Mission Sphinx Stepwell Ziggurat Alcazar Monastery Pairidaeza Chemamull Golf Course Makewap Mound Open Air Museum Ice Hockey Rink Maori Pa Ironically, you can build Moai if it is alone in a single forest.