Old Valyria in Game of Thrones might be a close depiction of the Ancieant Rome. The two cities have much in common. They both had a system of slavery, world renown roads and advanced technology for their time. Both cities lived a lavish and rich life based on a world dominion. Both the Valyrian and the Ancien Roman civilization were dominant on the contintents they were located on and kept their power through pure bloodlines by marriages within the ruling families and the elite. Like Ancient Rome, Valyria left behind a legacy that seems to be the base of legends even today. Also, both civilizations had well developed languages. George R. R. Martin says himself that he drew a lot from the history of the Ancient Rome while conceptualizing Valyria.
But, the iconography used in the depiction of Old Valyria in the GoT TV show might suggest something else. Old Valyria doesn`t look much like the Ancient Rome. It looks more like a ruined city in the moist and waterlogged parts of Southern Asia. Which leads us to one of the biggest Empires in that part of the world, the Khmer Empire. The capital city of the Empire, Yasodharapura and the Angkor Wat temple complex were the center of this Empire. Angkor Wat is the biggest and the best preserved religious monument in the world. And it`s similarity to Old Valyria is just stunning.
Check the gallery and draw your own conclusions about the mesmerizing similarity based on the buildings, the surrounding nature and the iconography present in Angkor Wat.