Kuvira's vine-ray cannon is modeled after a real weapon: WW1 German "Paris Gun", a massive siege super cannon manufactured by Krupp. Nicknamed "Big Bertha" by the French, it had a caliber of 238 mm and its shells were the first man-made objects to reach the stratosphere. It had an effective range of over 81 miles, and it was used to bombard the city of Paris. Parisians, unable to see it, often confused the shells to be bombs from a high-altitude zeppelin.
This episode had every single member of the Beifong family known to be alive featuring and towards the end of the episode, all within the same vicinity.