Beyond the Door to Hell, what should travelers see in Turkmenistan?

Whenever people talk about Turkmenistan, the conversation usually starts with the Door to Hell.

But after spending time exploring the country, I believe there are many other places that deserve more international attention.

Some examples include:

• Yangykala Canyon
• Koytendag Mountains
• Ancient Merv
• Ashgabat's architecture
• Akhal-Teke horses

For those who have visited Turkmenistan or work in travel, which of these places would you promote first to international travelers, and why?

I'd love to hear different perspectives from the Travel Massive community.