Contains some plot spoilers.<br /><br />I desperately tried to like this having first seen it aged eight, but what seemed exciting / scary back then, I find pretty lame now. It's in the style of Raiders of the Lost Ark or Romancing the Stone, but not half as good. Set in Central America (not in South America, where it claims Belize is ) the story follows the US Army setting up a low-frequency transmitter as a navigational aid to subs. As a precaution this 'beacon' is to be hidden deep underground and to help locate a suitable place is elite mercenary and caveman Rupert Wolfson. When men operating the transmitter mysteriously disappear, `Wolf' and some anthropologists help in the search which takes them deep into the mountain. Here they encounter unforeseen perils, including a race of temperamental albinos. Actually filmed in Alabama and Tennessee (Cathedral & Cumberland Caverns respectively) this suffers from dreadful acting and screenplay, plus lack of imagination as the 'mystery' unfolds (not to mention numerous continuity & editing errors) An atmosphere of intrigue and ambiguous wonder is created to (almost) good effect at the beginning, with the opening monologue discussing unexplored wonders of the Earth accompanied by eerie music. This ambience is lost after some badly directed action and almost ruins the following helicopter distorted lens sequence, meandering us through the unwelcoming landscape like a drunkard. `2001'-style wonder is paired with suspense as we enter the caverns, combining some good cave locations with matte artwork and photography. But the camera seems more interested in what our characters are doing. Before long the low budget is apparent and aside from some interesting monsters, we're treated to silly sets and costumes. Characterisation is based on racial stereotypes and the general level of stupidity of that person. Take our main character: he is suave Englishman Wolfson, acting as a consultant for the army; an expert<br /><br />fighter and all around good-guy. No personality flaws, only bad dress<br /><br />sense. Two ugly English (natch) play scientists who are specifically there to die. The female lead (obligatory love interest) is talkie (but not outspoken) Leslie. Working with the Anthropologists she helps extract long-dead remains but will scream when faced with a fresh one. Not too bright. The main American contingent play embarrassingly inept and unprofessional soldiers obsessed with working the transmitter as if their lives depended on it. Wolf's friend George's only importance to the plot is to tell Wolf about the mission. He is a lieutenant and an idiot. There are also several local Latin-Americans assisting the US, one is accident-prone Santos who acts as a plot device to attract the monsters. Acting is at best poor and veteran Robert Powell doesn't even try to get to grips with his (admittedly awful) script. Apparently the main script was being rewritten every day during the shoot and it shows! There are some good `Predator'-style effects as the humans are viewed as a pink glow through the Lemurians' eyes, but their rock-shattering scream was unconvincing. I did like the idea that the Lemurians are sensitive to ultra-sonic waves though. The plot badly loses its way. The buildup is painfully slow and when the 'mystery' is finally resolved, it's a real anti-climax (not giving anything away, let's say not exactly a Close Encounters moment) The idea of discovering creatures deep inside a tropical mountain landscape appealed to me, but `Secrets of the Phantom Caverns' is a letdown. Underground albinos!