At Earth's Core (1976)

The poster is better than the movie.

I missed this one when it came out in 1976 and I don't remember hearing about it. It's super cheesy with hilarious special effects and pretty bad acting. This was long before the omnipresent use of cgi of course, so you have to give them credit for going all out with the monster costumes. Based on an Edgar Rice Burroughs story and directed by Kevin Connor, it stars Doug McClure and Peter Cushing as scientists who accidentally drill through the earth's crust in their Iron Mole and end up in an enormous cavern filled with bizarre prehistoric creatures. The Mole was pretty cool and looked kind of steampunkish.

The Iron Mole getting ready to launch.

The sets are actually pretty nice and there are some totally awesome giant mushrooms. The scientists soon get captured by pig-snouted minions who are telepathically controlled by evil reptile-birds. They have enslaved humans and McClure and Cushing will eventually have to fight them to free the slaves and themselves. There are plenty of action scenes as McClure must battle many strange underground beasts as well as jealous slaves. And there's lots of fire too as they are after all "At the Earth's Core". And last but not least there is a very attractive slave princess played by Caroline Munro, who is easily the best thing about this movie (besides the mushrooms).

Awesome mushrooms.

Doug McClure shows off his biceps to Caroline Munro.