Pretty — spectacular (6)
I believe the answer is:
scenic
I believe this clue is a double definition.
'pretty' is the first definition.
(I've seen this before)
'spectacular' is the second definition.
(thesaurus)
(Other definitions for scenic that I've seen before include "Offering pleasant views, say route" , "Dramatic, theatrical" , "Having attractive views like some routes" , "They are usually the long way round!" , "Like an attractive view" .)