Some of the earliest Umayyad "palaces" had almost no defensive purpose at all. They were built in the desert to be seen, not to survive a siege.

One page of the Blue Quran, gold script on indigo parchment, would take a skilled scribe weeks. No one agrees on exactly where it was made.

Durham Cathedral's ribbed vault, often called the first Gothic structure, went up 308 years after the same system was already standing in Cordoba.