3000 years ago, Su'Agat was the center of human civilization. Few written records remain due to its horrible downfall - the entire city and its environs were consumed suddenly by churning sands that became the Glass Desert. Today, bits and pieces of carvings and other artifacts are found daily in the desert, giving us a fuller picture of what this ancient civilization was like.
The largest remaining piece of Su'Agat is its collapsed palace. It once sat at the peak of a large ziggurat, and so seems to have remained above the sands that consumed the rest of the city. Unfortunately, the palace is collapsed and has long since been looted many times over. And yet, there are reputed to be rooms within the palace that remain sealed off and stubbornly refuse to let even the most well-equipped treasure-seeker in… what's worse, many have died from magical traps left active all these years later.
Myth says that Su'Agat was not just the center of all things in the world, but also of magic. Its rulers reputedly studied and were experts in all the known forms of magic, and were experts in them all: sorcery, death art, blood magic, corruption Magic, and inscription.
The true reason for its downfall is unknown, but the elves and dwarves say that, around the same time of Su'Agat's fall, Verden itself suffered an intensely traumatic blow that forced the elves to retreat Taelmoor and the dwarves to go into the Sunkensleep. It's highly likely that the two events are correlated.