Paris at 1:1, from a single prompt
The Eiffel Tower, the Seine and the city around them, rebuilt as a 3D model you can fly over in your browser.
Read the updateOblivion's Imperial City, rebuilt block by block as a world you can actually walk through.

Take one of the most recognizable cities in gaming and see if an AI could rebuild it as a place you can explore, not just a picture of it.
The whole thing lives in the browser. Describe the districts, the walls and the tower, then keep pushing on the details until it feels like the place you remember.
Interiors, more districts, and the files so you can build your own version.