Sci-Fi's Early Forerunners
There are a couple of about the exact origin of science fiction in man's early history. One story thought to be sci-fi's genisis is the Hindu epic Ramayana, circa 5th to 4th century BCE. It describes, among other technologies, vehicles capable of aquatic exploration and flight, as well as weaponized cities. Another remarkable story hails from Japan entitled The Tale of the Bamboo Cutter, of which tells of a moon princess sent to Earth to escape the ravages of a galactic war.