Roma

From SFWiki

Roma was the name of the capital city of the Empire Romae. It was destroyed in 0 PR by the Great Rising. Its ruins are located on the sea floor between the islands of Pompeii and Tuscan, at the east.

Roma was considered an exceptionally enlightened and modern city for its time. Its engineers were extremely talented and it was a powerful center of commerce for the entire world. It was from here that the great Empire Romae ruled the world.

However, the Great Rising destroyed Roma utterly - washing it from the face of the earth - and with it, 90% of the nobility of the Empire, including the Emperor himself. Without a central point of government, the Empire collapsed into civil war.