There are 3 different arenas, Colisseum, Palace and Desert.
The Desert and the Palace will probably be familiar to you, since 95% of the models are copied from existing places, only kinda "new" zone is the colosseum.
Some pics:
And 2 videos from Youtube:
I knew about the survival arena since some months ago, but I had not enough info to be posted that was worth a post here, plus Babbe is missing so who knows, the blog is kinda abandoned, sorry for that, I will try to take more care about it!