What Kryptonian city does Zor-El protect with a force field in Supergirl? Argo City. In the film, Zor-El activates a force-field system around Argo City as Krypton collapses, preserving the city and its inhabitants from the planet’s destruction.
Argo City is one of the most important locations in Supergirl’s origin. It is associated with Kara Zor-El’s family and explains how she experienced Krypton’s destruction differently from her cousin, Kal-El. The city survives as a separated fragment of Krypton, floating through space inside its protective barrier.
This detail comes from Supergirl’s comic-book mythology, where Argo City survives Krypton’s explosion through technology created or used by Zor-El. It is easy to confuse Argo with Kandor, another famous Kryptonian city, but Kandor is traditionally the city shrunk and bottled by Brainiac. Gotham City and Metropolis are Earth cities and are unrelated to this origin event.