Kunya-Urgench (Old Urgench) in my opinion is the most impressive of the Turkmen WHS. It's a flat, deserted, hot stretch of land dotted with monuments here and there. The wonderful minaret (the oldest of its kind remaining in the world, and one of the highest buildings from its period) draws your attention right away. The adjoining Tekesh Mausoleum is now under construction, but its turquoise conical dome is still visible.
Visiting the site is well organized: there's a footpath that links the monuments. Some of them can be visited inside too, but often they have been taken over by groups of pigeons. Worth mentioning is the Torebeg Khanum mausoleum which has a wealth in mosaics. Those under the dome are put together like a calendar.
What I liked about the atmosphere here is that it still is a local pilgrimage site. You can see stones placed on top of each other for good luck. There's also a spot where little cribs are left by women who pray to become pregnant.
The site is also still littered with graves. This is said to prevent authorities from excavating here. There must be so much more left underground of this once powerful city!