Unknown World is an odd little 1951 sci-fi B-movie that offers a twist on the usual 1950s nuclear paranoia movie. With a cataclysmic war imminent due to the invention of the H-bomb, a team of dedicated scientists decide the only hope is to find a sage refuge for humanity deep beneath the earth. Since, as everyone with even a passing knowledge of geology knows, the core of the earth is cooler than the surface and the interior of the earth is a honeycomb of underground rivers and interconnected passages, and fresh air is of course plentiful, they are able to convince a wealthy media tycoon to finance an expedition.
All they need to do is enter an extinct volcano, and keep going. They will need to go thousands of miles beneath the surface, but that’s no problem since they have the amazing nuclear-powered Cyclotram, an amphibious go-anywhere tractor that is also a tunneling machine.
Accompanied by the media tycoon, the team (including a glamorous girl scientist) sets out. What you naturally expect them to find are lost civilisations or at least prehistoric monsters, but that’s not what they find at all. This is a serious science fiction movie. Although they do encounter some dangerous isotopes, and they do have various adventures along the way.
The effects are OK for a low-budget effort of this vintage, and there’s plenty of entertaining bad science. And even with the glamorous girl scientist it’s not as sexist as most movies of its type and era.
It has to be admitted that Unknown World is a little short of excitement, but is amusing enough if you’re a fan of 50s B-movies. And it naturally has a Serious Message. This was the 50s. It’s available on DVD, although it’s only worth buying if you can pick up a copy for a couple of dollars. It’s really one to rent rather than buy. I saw it on free-to-air TV, so I’m not complaining.