And goes through these strange mountains (3,5)

I think it could be either:

Which length description are you looking for?:

3,5

the andes

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'and goes' is the definition.
I can't tell whether this defines the answer.

'these strange mountains' is the wordplay.
I cannot quite understand how this works, but
'mountains' could be 'andes' (I've seen this before) and 'andes' is found within the answer.
The remaining letters 'the' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).

'through' is the link.

Can you help me to learn more?

(Another definition for the andes that I've seen is " Range".)

I've seen this clue in the Evening Standard.

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