"Stargate" productions center on the premise of a "Stargate," a ring-shaped portal that enables rapid transportation to other stargates located cosmic distances away. The story begins when one such device is discovered on Earth. The 1994 film and subsequent television series depict how the device is kept under the control of the United States government, who use it to conduct interplanetary missions by dialing the thousands of stargates located in the galaxy, which are the legacy of an ancient civilization. The expeditions originally had the goal of acquiring extremely rare resources, new technology and detecting threats; but often face scientific and humanitarian issues and the dilemmas of interacting with different societies. Finally they resulted in a unified "United Nation"-coalition to better support the constant need to continue the program to defend Earth from invading aliens.