That the people of Kizzuwatna made the first iron swords. Not only iron...but meteoric iron alloy. Space swords. The Hittites were not feared for their very progressive religious and legal codices....they were feared because three guys on a chariot (your chariot would have 2) wielding weapons that could quite literally hack right through yours like in a movie. ( you can do this at home with adult supervision...really quite impressive), was a perfectly good excuse to show fear. The ones who thought it was whatever, are vulture s*** around Kadesh as we speak. Bravery absent brains is the formulation for death. Do not try that one at home please. You'll have no fun.
It was good to have the Kingdom of Kizzuwatna as a vassal. Fine weapons, fine chariots, the best horses...and the greatest of Queens.
For me it isn't a historical fact but one from the field of science.
That every element in the universe heavier than hydrogen has as it's origin fusion in the heart of a star. The elements that make up the human body - carbon, iron, oxygen, ect were birthed into existence in the core of a star that later erupted in a supernova, scattering those elements into great dust clouds that later condensed to form our sun and it's orbiting planets, including Earth and everything in existence on it. An iron atom in your left hand could also have as it's origin a different star than an iron atom in your right.
King James I of England (aka: James VI of Scotland) used the term "Great Britain" for the first time on 20th October 1604. However, Parliament would pass the Act of Union over a century later.
"Seeing that there is but one head of both peoples, which is Ourself, We have thought good to discontinue the divided names of England and Scotland out of Our Regal style, and do intend and resolve to take and resume unto Us the name and style of King of Great Britain."