Timeless moments about big film showing requirements for climbers? (3,5)
I believe the answer is:
ice picks
'requirements for climbers?' is the definition.
(tools used by climbers)
'timeless moments about big film' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'c' (abbreviation for 'circa') and 'c' is found within the answer.
'big' could be 'epic' (similar in meaning) and 'epic' is found in the answer.
This explanation may well be incorrect...
'showing' acts as a link.
(Other definitions for ice picks that I've seen before include "rock-cutting tools" , "mountaineers might need them" .)