Though a notable cause I am not sure if Christiania really is of outstanding universal value the infrastructure and architecture are all essentially a disused army camp, and I don't think the famous bikes would be enough to meet the work of human creative genius criteria. It would also create problems of sovereignty arising from Micronations, but hey this is a just for fun fantasy list so perhaps that is not important.
The Kibbutz idea sounds more reasonable. Though I must admit I don't have much knowledge of them and I wont pass off the quick glance at wikipedia as actual understanding but if someone does know a little more on the issue I would be interested to find out.
Socialist ideals don't really manifest themselves on the list, the planned industrial towns such as New Lanark, Saltaire, (Crespi D'Adda?) etc. show some of the early ideas that blossomed into the Socialist movement, but it is pretty tough to pin down political ideologies associated with particular sights. Independence Hall, Statue of Liberty and Monticello in the USA are all keenly associated with Liberalism, and there are a fair few Palaces in Europe associated with Monarchical Absolutism but political ideologies (independent of religious ideologies) don't seem to feature much.