THE LOST CITY is a famous serial that came out in 1935, the same year as THE PHANTOM EMPIRE. There were some similarities, with strange underground superscientiffic characters menacing the world with their insidious devices. A comic book version of THE LOST CITY came out, but it lasted for only two installments. Here is part one.
THE LOST CITY ( Comic book version ):
THE LOST CITY ( Complete serial ):