I saw this movie (from the 50s?) on TV as a child in later 60's. I recall it being b/w. I recall somewhat clearly a number of 'explorers' on a distant planet moving up a narrowish path/ledge along the side of a mountain. Heading to a City/Building they had seen at the top.
Key point was them encountering some 'giant ants' on the path and having to get [fight?] past them. The ants were possibly claymation style but in b/w they were very surreal looking and worked well to my young mind.
What is really tugging at me to find this movie is something about the city they reach. I believe the ants may have been workers for some other race. And most importantly something about time - either distorted or it is slowed or ends up standing still.
I have searched all the lists and researched those I thought may be close.
What is worse is that I swear I saw it as part of a collection DVD set and the name was so obvious that I didn't worry about finding later! Yeah Right!