The Phantom Empire

A 1935 serial in 12 chapters with Gene Autry as The Singing Cowboy, mixing the Western and science fiction. Gene is caught between the Thunder Riders, from the underground city of Murania and a group of normal thieves, who want the radium from the city. Meanwhile, the city itself is on the verge of revolution. Furthermore, if Gene is captured by either one, he'll miss being able to do his radio show and lose his ranch.

The film was Gene Autry's first starring role, and his only film serial.

Homaged in The Secret Empire in Cliffhangers.

Tropes used in The Phantom Empire include:

• Blondes Are Evil (Queen Tika)
• Cattle Punk
• The Coconut Effect: Since it has a radio Show Within a Show, it actually shows coconuts being used to make horse sounds. Being partly a Western, it no doubt had many traditional examples too.
• The Danza, Gene Autry, radio star, as Gene Autry, radio star.
• Elaborate Underground Base: The whole Phantom Empire.
• Film Serial
• Ice Queen (Queen Tika)
• Kid Sidekick: the Baxters (who call themselves the Junior Thunder Riders)
• New Old West: borderline, like many films up to the 1940s which used a modern-day setting but took place in the West and included many Western tropes