360CityArena

We present 360CityArena, a benchmark for evaluating the urban exploration capabilities of Embodied Agents within a photorealistic environment constructed from 360° videos. Existing outdoor benchmarks either lack sufficient photorealism and complexity, resulting in a considerable gap from real-world urban environments. 360CityArena is built on a realistic reconstruction of the Akihabara district in Tokyo, Japan, using 602 360° video segments covering 85 streets, and consists of 175 meticulously human-crafted tasks. It encompasses three task categories — Environment Understanding, Path Reasoning, and Spatial Reasoning — covering fundamental abilities required for urban exploration, such as localization, landmark search, path planning, and relational spatial reasoning, thereby enabling comprehensive evaluation in realistic urban scenes. Our evaluation using state-of-the-art LMM-based agents shows that even the strongest model, Gemini-2.5 Flash, performs far below human level (human: 77.3% vs. Gemini-2.5 Flash: 17.1%), revealing substantial challenges that remain in city-scale embodied navigation and reasoning. 360CityArena provides a necessary and challenging testbed for photorealistic urban-district navigation and spatial reasoning.

360CityArena is built on a Realistic Virtual World of Akihabara reconstructed from 602 360° video segments over 85 streets. The videos are projected onto a spherical surface and organized into a navigable pose graph in Unity, so agents traverse prerecorded 360° trajectories rather than moving freely in 3D. The resulting graph forms a single connected component with 193 nodes and 305 edges, with a mean branching degree of 3.16. Geographically, it spans roughly 750 m north–south and 650 m east–west around Akihabara Station — a dense, information-rich district with narrow sidewalks, complex building layouts, and abundant electronic signage. Each street is captured in both directions to reflect direction-dependent visual changes.