The site of Nisa is about 20 minutes drive by taxi from Ashgabat. Nisa was the 1st ancient capital of the Parthian state, built around 200-100 BC. Old Nisa fortress was a royal residence with palace, and temple buildings, large wine warehouse and other warehouses with ample space. The city walls were 8-9 meters thick and were reinforced by 43 rectangular towers. When in 226 AD the Parthian Empire fell Old Nisa was destroyed. So much to history, and yes there is not much to see nowadays. It is a Unesco World Heritage Site; excavations by expert teams have uncovered some treasures which are exhibited in the Historical Museum in Ashgabat. Walls have been reconstructed but there is no information at all, and the reconstruction works are a bit shabby. I have seen many ruins of ancient sites in several continents but nowhere I needed so much imagination as at this historical site what the city would have been at that time. In short the site is unremarkable.
I was there on a Sunday, nobody charged an entrance fee and no guide was at site. If one has ample time and nothing else to do then visit this site.

Interesting. Great location. Get a guide to discover just what the mounds are or were back in history. The most developed archaeological site in Turkmenistan. Much more developed than Merv or Margush.