The wall was built 8 thousand years ago and the texts suggest that it was built after the battle for the dawn, which means the Others were considered to have been "defeated". Evidently, there are several considerations to be made when we discuss those explanations, primarily, and of tremendous value, is the fact that the history of Westeros as we know it and as our characters have access to, has been written by the Andals who only arrived in Westeros 2 thousand years later. When they invaded, they imposed their writing system, which made the runes that were previously used, redundant. Any people who write a story, can write turn it to their advantage, therefore making it unreliable. GRRM wrote those stories basing them in our own history. If we simply take for example the school taught nonsense that "Christopher Columbus discovered America". Christopher Columbus could not have discovered America because, as we know, then he crossed the pond and reached land, there were people already living there. You can't claim to "discover" something that is already inhabited. Leif Erikson travelled to America some 500 years before Columbus and might have been the first one. The only action that Columbus can be undoubtedly recognized for, was the spreading of diseases so widely in the continent that he killed well over half the indigenous population. The reason why the schools teach (or taught when I was in school) that Columbus discovered America, is because the three major navigators at the time: Italy, Spain and Portugal, were obsessed with adding their names in the history books and so logged their every movement, highlighting their actions and their people as heroes while glossing over the fact that they were often sexual predators, violent, dishonest and ignorant men.
The Westerosi history of those constructions also has some questionable details. As per the books, during the age of heroes, Bran the Builder helped build Storm's End when he was a boy and designed Hightower in Oldtown (while others claim it was his son, another Stark with the creative name "Brandon"), then he survived the Long Night, which lasted a whole generation, and left it unscathed to build Winterfell and the Wall.
Logic dictates that Winterfell was actually built during the Long Night. I wrote about that before here. The consideration against real world is rather big. In our world, the oldest structures aren't livable. The Knap of Howar is approximately 5500 years-old and it was stone built in a piece of land that was dug into the dirt. It has no roof, no ceiling and no windows. The Megalithic Temples of Malta are approximately 5 thousand years-old and free-standing, which was rare at the time, but if you search, you'll see they haven't stood the "test of time". There's an outline of what they were, some big rocks piled... The wall of Jericho is estimated to be about 10 thousand years-old and it's in ruins, so the fact that the structures in a World of Ice and Fire withstand the test of time when GRRM is so consistent with his writing and accurate in his consequence, gives credence to the concept of magic, and more specifically, blood magic.
Westeros primarily was a place of "creatures", with the Children of the Forest and the giants. When "men" first arrived, they plowed the land and built motte-and-baileys forts that later were changed into stone constructions. Many of them are ruins, like the Fist of the First Men or Sea Dragon Point. Moat Cailin is also mostly in ruins, but extremely effective regardless.
The Andals invaded Westeros with iron instead of bronze and they had far superior engineering and technology, which is expected, as they were an older civilization, so it was akin to the idea of the Christians arriving in South America imposing their religion on the indigenous people. What chance could pacific nature duelers have against people who had arrived with malicious intent? Their invasion was nearly absolute. The only exception was the North. You can read more about that here.
But from one country to the next, development depended on the monarchs of that land, so the North was very vast and the Starks were respected by their vassals and lords, but had to allow the lords to exercise some of their own laws around their lands simply because otherwise, they would lose support. The Boltons still did that, despite laws to the contrary, which is how Ramsay came to our story. The Starks could contribute to the growth of the North to a certain extent, by the development and growth of the "gift", "Winter Town" or offering their workers to help maintain minor houses, but they couldn't possibly presume to control every piece of their land. The Lannisters, on the other hand, were far more ambitious and concerned about their image, so they made sure to have Lannisport as an outstanding city. The Citadel was also extremely well developed and by the time the Targaryens conquered and transformed Westeros in one country, Aegon knew what he wanted to change. His vision of King's Landing was brought to fruition and it grew to surpass Lannisport or the Citadel.
Essos, however, is an older and much vaster continent. From the far east with Asshai and their development in the dark, which is unique in every aspect and must have happened over hundreds, if not thousands of years, to the magnificent, if not mythical city Valyria, Essos evolved with its people. While Asshai had developed in mysticism and dubious magical practices, they grew, but with a strong focus on the occult. Going towards the East, Yi Ti is the place where the Five Forts stand. They were built before the Golden Empire and the suggestion is that it was built by the order of a character known as the Pearl Emperor. It's a legendary story, evidently, somewhat akin to the biblical tales of the old testament where a person is said to have lives for thousands of years and the day or night were equally represented by fables where the day was represented in their stories as the 'Maiden-Made-of-Light' and they say she "turned her back on the world so the 'Lion of Night' arrived to "punish the wickedness of men", which means they took a religious approach to the situation. The Faceless men have a statue of the Lion of Night that Arya describes, which means they simply believe the Lion of Night is one face of their god, but the consideration is that the Lion of Night is the Long Night. That would mean the Five Forts were built during the Long Night. How? I dunno. They are extremely large, each being able to house ten thousand men and the walls are nearly one thousand feet high, which means higher than the wall itself.
Qarth as we know now is fairly new, but the Qaathi people lived in the land we know as the Dothraki Sea. That was because when the Dothraki became nomads, the Qaathi were pushed away. Qarth does have impressive architecture, from the triple walls, the Temple of Memory, the Garden of Gehane and the "house of the undying" itself.
I realize I haven't even covered half of Essos and I need a break. This is so long. Jeez! I'll be back later, miss Suuda.
