Tourist sees some bridge on isthmus (10)
I believe the answer is:
rubberneck
'tourist' is the definition.
(rubberneck is a kind of tourist)
'some bridge on isthmus' is the wordplay.
'some bridge on' becomes 'rubber' (I can't explain this - if you can you should believe this answer much more).
'isthmus' becomes 'neck' (I've seen this before).
'rubber'+'neck'='RUBBERNECK'
'sees' is the link.
Can you help me to learn more?
(Other definitions for rubberneck that I've seen before include "Slow to see accident" , "Gawper" , "attribute useful to contortionist" , "Turn one's head to stare foolishly" .)