Only the city of Zootopia stands.

Most of their world has already been conquered by those strange furless animals that called themselves humans, they aren't that strong themselves but their technology was powerful enough to force even the bigger and stronger animals to submit, the only remaining human civilization that still remained resisting against them was the city of zootopia thanks to being their most advanced and biggest city, making it harder to totally conquered without killing most of them, which would be a waste of great infrastructure and slave resources.