Mountain sees First Lady taking breather (7)
I believe the answer is:
everest
'mountain' is the definition.
(Mount Everest)
'first lady taking breather' is the wordplay.
'first lady' becomes 'eve' (first woman in the Bible).
'taking' says to put letters next to each other.
'breather' becomes 'rest' (I've seen this in another clue).
'eve'+'rest'='EVEREST'
'sees' is the link.
(Other definitions for everest that I've seen before include "Huge achievement - highest climb" , "Highest peak" , "Himalayan mount" , "The world's highest mountain" , "A mountain to climb" .)