  Digital twins are now a staple of wireless networks design and evolution.
Creating an accurate digital copy of a real system offers numerous
opportunities to study and analyze its performance and issues. It also allows
designing and testing new solutions in a risk-free environment, and applying
them back to the real system after validation. A candidate technology that will
heavily rely on digital twins for design and deployment is 6G, which promises
robust and ubiquitous networks for eXtended Reality (XR) and immersive
communications solutions. In this paper, we present BostonTwin, a dataset that
merges a high-fidelity 3D model of the city of Boston, MA, with the existing
geospatial data on cellular base stations deployments, in a ray-tracing-ready
format. Thus, BostonTwin enables not only the instantaneous rendering and
programmatic access to the building models, but it also allows for an accurate
representation of the electromagnetic propagation environment in the real-world
city of Boston. The level of detail and accuracy of this characterization is
crucial to designing 6G networks that can support the strict requirements of
sensitive and high-bandwidth applications, such as XR and immersive
communication.
