Film / Undersea Kingdom

A Republic serial from 1936. The plot is basically the classic "Atlantis found" story. U.S. Navy Lt. Ray "Crash" Corrigan, Professor Norton and his son Billy, Joe the panicky sailor, and the Intrepid Reporter Diana Compton (and two other guys with a parrot, but they show up so little it doesn't count) journey to Atlantis, a "continent" that is under a dome of a gold/copper alloy. There they have misadventures trying to prevent the evil Unga Khan from destroying/conquering Atlantis, and eventually the "upper world."

See here and here for the episodes of Mystery Science Theater 3000 that featured the two installments of Undersea Kingdom.

Undersea Kingdom contains examples of: