This paper introduces CameraCtrl II, a framework that enables continuous and dynamic scene exploration through a camera-controlled video diffusion model. Previous camera-conditioned video generative models suffer from diminished video dynamics and limited range of viewpoints when generating videos with large camera motion. We take an approach that progressively expands the generation of dynamic scenes---first enhancing dynamic content within individual clips, then extending these capabilities to create seamless explorations across broad viewpoint ranges. Specifically, we construct a dataset featuring a large degree of dynamics with camera annotation for training while designing a lightweight camera injection module and training scheme to enhance dynamics from pretrained models. Building on these improved single-clip capabilities, we enable extended scene exploration by allowing users to iteratively specify camera trajectories for generating coherent video sequences. Experiments across diverse scenarios demonstrate that CameraCtrl II enables dynamic scene synthesis with substantially wider spatial exploration and enhanced dynamics than previous approaches. We will release the dataset and code.