The City Watchman's Sentry Box at Norfolk Crescent, Bath, UK. Grade II* listed.
In Georgian times, prior to the existence of a Police force, the resident's hired a Watchmen, and built this extravagent stone hut (based on the Monument of Lysicrates in Athens) for him to shelter in, or lock-up suspects.
My 3D model from photos generated with photogrammetry software 3DF Zephyr v6.000 processing 409 images.
Unfortunately I did not take shots from high enough to correctly render the roof.