Khiva's Ichan-Kala is the most complete example of a fortified Central Asian city, its mudbrick walls enclosing minarets, madrasas, and palaces largely unchanged since the 19th century. It's small enough to explore fully on foot in a day, but the light at sunrise and sunset over the Kalta Minor minaret is worth staying an extra night for. Just outside the walls, Khorezm's carpet weavers still work traditional looms passed down through generations.
Quieter than we expected for how well-known it is. Early morning is the way to go.
A bit touristy at the main spots but wander two streets over and it's completely different.