Look at the following image taken from anandus on the screenshot thread:
Vilnius has an Amphitheatre, as shown by the thick white border around the Great Work slot. (Buildings that haven't been build yet are shown with thin grey borders around their Great Work slots.) But Vilnius only produces 1 culture per turn, the yield of an Amphitheater in BNW without a Great Work.
Lodz and Wroclaw on the other hand produce 3 culture, but look to have the same buildings as at Vilnius. It could be that that culture is from a Pantheon, but in the other screenshots it doesn't show the Polish cities to have any religion.
At the minimum we can conclude that having a Monument is no longer a prerequisite to build an Amphitheater. (Or that Firaxis screwed up when they created the sample game.)
Another possibility is, as Poland has 5 cities, that Vilnius is the 5th city, Legalism (or maybe the Tradition opener) now gives a flat +2 culture in your first four cities instead of a free cultural building (the current implementation of Legalism has its issues, so changing it wouldn't be unlikely), and that the Monument no longer exists. Of course, having a Monument that gives 2 culture when the base of the Amphitheater is only 1 at a significantly higher cost doesn't seem to be balanced.
Vilnius has an Amphitheatre, as shown by the thick white border around the Great Work slot. (Buildings that haven't been build yet are shown with thin grey borders around their Great Work slots.) But Vilnius only produces 1 culture per turn, the yield of an Amphitheater in BNW without a Great Work.
Lodz and Wroclaw on the other hand produce 3 culture, but look to have the same buildings as at Vilnius. It could be that that culture is from a Pantheon, but in the other screenshots it doesn't show the Polish cities to have any religion.
At the minimum we can conclude that having a Monument is no longer a prerequisite to build an Amphitheater. (Or that Firaxis screwed up when they created the sample game.)
Another possibility is, as Poland has 5 cities, that Vilnius is the 5th city, Legalism (or maybe the Tradition opener) now gives a flat +2 culture in your first four cities instead of a free cultural building (the current implementation of Legalism has its issues, so changing it wouldn't be unlikely), and that the Monument no longer exists. Of course, having a Monument that gives 2 culture when the base of the Amphitheater is only 1 at a significantly higher cost doesn't seem to be balanced.